False, it was Quel’thalas who left the alliance. The alliance (wildhammer) helped evacuate and host elves (humans) who still wanted to be friends.
From the official WCIII manual
Despite the high elves' official departure from the Alliance, some elves still remain true to their former human and dwarven allies. The altruistic priests of Quel'Thalas refused to abandon their roles as healers and agreed to remain in Lordaeron despite the edicts from their reclusive masters in Silvermoon.
I’ll google the highlights of this, as it takes two searches to learn.
King Terenas of Lordaeron reminded them that nothing of Quel’Thalas would have remained if not for the hundreds of humans that gave their lives to defend it, but nevertheless, the high elves largely abandoned the Alliance and retreated to their kingdom.
The elves were suffering from great withdrawals after being cut off the Sunwell because of its destruction. Due to the unreasonable orders of the Alliance leader Garithos, Kael’s people were forced to ally themselves with the Naga and fled to Outland.
The healthiest blood elves led by Kael’thas Sunstrider, prince of the ruined Quel’Thalas, also joined his army.[8] Garithos did not enjoy having to work with the blood elves[9] or dwarves,[10] believing that the Alliance’s mission should be to preserve humanity above all else and that the Alliance should never have accepted the elves in the first place.
The observatories repaired by the Alliance Remnants discovered that an undead strike force was coming from the west. Garithos returned to the front and left Kael’thas awaiting orders. Then, an Emissary sent by Garithos informed Kael’thas that he had to engage the strike force from the west, but also recalled all foot soldiers, cavalry and support teams to the front, leaving Kael with only his blood elven troops. Garithos had hoped that the elves would fall before the Scourge, and no longer be his problem;[14] the missions given to Kael’s greatly reduced force were intended to be suicidal, impossible for the elves to complete.
The Blood Elves leaving the Alliance was during this event. Before Kael’Thas officially betrayed his people. Theres a lot of Elf history between the major times that is important also.
You speak of Making do with what you’ve got yet you simply are not doing that, You do not have High elves, You have Void Elves, You should be making do with Void Elves
As it stands, The High Elf population is possibly the smallest one around, And it shrinks every day, The Void Elf Population while not large, Is still LARGER than the High Elves, There simply isn’t many around anymore.
That’s when the blood elves tried to go back to the Alliance with Garithos indeed, but that was a whole deal with just him. They had no deals with Stormwind or anything. Stormwind formed its own Alliance. Formally the name is “The Grand Alliance”.
I met this Emissary on his travels, he handed me a small pouch of an unknown substance and told me to mix it with my ale. I therefor became the first “High Elf” but only for about a half-hour.
The Alliance knew they were using volatile magic. That was the entire point of spying on them. Also abandoned? Look who is talking, the Silvermoon elves left the Alliance and told Terenas they were leaving because the Alliance somehow allowed their forest to burn((which Terenas diplomatically replied that if not for the Alliance there wouldnt be a forest anymore)
I said a core race.
Core races and allied races are a bit different. 
EDIT: The blood elves have been a Horde core race for 14+ years now. The void elves have been an Alliance allied race for only 4 years.
A bit of a difference there.
Sorry to burst your bubble, but this is where you’re entirely wrong on this one. Void Elves are just as close to High Elves as to the Blood Elves. And the funny thing is, you only have to look at the devs comments and also look at Alleria.
Void Elves = Blood Elves = High Elves. They are all of the same, biggest difference mostly being political with there names.
And the point have skipped over your head
Though there is no lore to say why we have High Elf Wayfarers in Telogrus Rift, but yeah, future Void Elves maybe? But Void Elves are pretty much High Elves, just the same sense as to Blood Elves are also High Elves. Both groups of different political views…
You talking about how only Umbric and his followers were captured to be transformed by Void Etherals into becoming more Void Etherals? The transformation was interupted when Alleria jumped in to save him and his followers.
Just remember , blood elf had high elf customization 1st 
if they were the same then why did you spam the forums for years, reject them and demand to get a clone of blood elves
the difference between a void elf and a blood elf is far more then political. its actually biological and that was the justification for their existence as an allied race in the first place
They are functionally the same other than the unlocking (which you may argue makes them more valuable), some ARs are way more played than some “core” races.
Sorry but wrong. Blood elves are biologically, and culturally the same as High elves. Void elves, again, have been biologically changed by the void, and by extension so has their beliefs and culture. Blood elves still practice high elven traditions, use High elven weapons, wear High elven clothes, live in the High elven capital - Blood elves are the inheritors of the High elven story. They even both worship the Sunwell together.
Are they technically both High elves? Yes, but if we are to compare who’s closer, Blood elves are obviously the choice. Even the devs said as much themselves in the interview about the High elven customizations.
Not really otherwise they wouldn’t have changed their name and have differences to those who continue with the name HE.
Blood elf society evolved drastically after the attack on Silvermoon, and again after the Draenei saved the sunwell.
IDK why Belf players refuse to acknowledge development of their race lol.
It’s like saying gilneans keep the same culture or forsaken are the same as old Lordaeronians or even that Stormwind is the same as the OG Stormwind.
Did they though? originally they didn’t get the blue eyes until they introduced the natural skin colours to both. And if hair colour was the issue, you could always go bald.
The demonym, Void Elf, already comes jam-packed with suggestions about their social-, cultural-, and political identity.
Oh please, there is no biological difference. Heck, a blood elf shadow priest is probably closer to the void then said a void elf hunter and yet you think the void elf hunter is a different species?
It is political, namely which faction the two have decided to work with.
On the contrary, Blizzard said they didn’t want established patterns when creating new Allied Races, which is why Vulpera are an AR (they’re technically not a “Goblin subrace” and yet are their equivalent AR).
So the whole “ARs were designed to be different species” has been completely debunked, especially considering how Kul Tirans and Humans are confirmed to be the exact same race biologically speaking. Same goes for Mechagnomes and LF Draenei, the latter even having regular Draenei children when procreating.
Except the name change wasn’t a cultural shift, nothing had changed after they became Blood elves. They didn’t cease to practice their High elven traditions, or beliefs, in fact they still honor those traditions to this day. The only sort of High elves Blood elves differ from are Alliance High elves, who’ve departed from their High elven roots further than any Blood elf on Azeroth. Keeping the name “High elf” doesn’t mean they are the “truer” high elves.
How they changed is an example of High elven behavior, they make up the majority of the High elven population. Even Lor’themar mentions in the heritage questline (that turns you into a High elf) that “tragedy” does not define their people, how they overcome tragedy defines them.
If something tragic happens to a group of people, and they change to overcome it, they aren’t suddenly a different group of people. You’re simply trying to use the name change to correlate that they’re somehow not the same race they were before, which is completely illogical.
Development doesn’t change who they are, they will always be the example of how the High elven race overcame the tragedy of the attack on their people, the “name” doesn’t signify any cultural change. It was only meant to honor their fallen.
“A wife does tend to be someone special to her husband.” His voice was thick with rage, humiliation, and despair. He reached into the front of his robe and wrenched a thin gold chain from around his neck, hurling it at Baenan’s feet. The necklace boasted no beads or pendant, just two exquisitely crafted rings, a man’s and a woman’s, high elven in design.
“You think I do not know what I am? We sin’dorei were given a choice: our integrity or our well-being. As if that were any kind of choice at all. I chose my well-being. My wife chose her integrity.”
Looks to me they gave up alot more then the high elves every did.
Choosing their well-being doesn’t make them any less high elven, in fact that is exactly how the High elves have behaved for countless years. Closing themselves off from the world, with only their survival in mind. Although with the Sunwell’s restoration this is completely moot point as the use of Kael’thas’ siphoning is no longer required of Blood elves.
“Alliance” High elves no longer practice their High elven traditions, they wear human clothes, live in human cities, breed with humans, and have practically abandoned everything that has made them “high elves” Elisande herself goes over this in her speech as she confronts each group, and even says they are not worthy of the name “High elf”
edit
And by the way, the “integrity” the wife speaks of refers to her choice to seek refuge among the Alliance over struggling to survive among the Silvermoon ruins, and rebuild their home. Who’s more High elven I wonder, the elf who stayed to help rebuild their nation, or the elf who abandoned it for a comfortable bed among the Alliance? Vyrin is the very example of an Alliance high elf who’s abandoned their their culture and people in favor of their alliance hosts.
note
If Vyrin had a problem with the Blood elves siphoning magic from creatures, I can only imagine how she would feel about the Void elves corrupting and twisting baby animals in their eggs into subserviently voidcraft.
Since the Sunwell’s restoration what changes the Blood elves made to survive are no longer even practiced, which essentially returns them to how they were before the attack ever occurred, while the Void elves continue to practice even darker magic in their quest for power. Are we still gonna say Void elves are closer to High elves?
Blood elves changed drastically. Because of their compulsion and need for mana becoming much more desperate and ruthless. Even their entire color scheme changed even from blues and silver to red, gold and fel green, and even the mounts they used. This was even reflected in Warcraft III.
Even the fact that they decided to ally with the Horde represents such shift. As otherwise they would’ve rejected any faction.
Another example is the Blood knights which became a huge presence in Q’T despite not existing before.
Which leads to the second change after the Draenei saved them with the elves becoming much more in love with the light.
The ones who kept their names are HEs are indeed much more true to their roots, and rejected these drastic changes.
If the classic conservative vs liberal if you will.
? When did I say anything about race, I’m talking about society.
That being said in WoW race is a very subjective term, and even a change of name does change your race. After all the game treats kul’tirans and humans are different races despite both being humans.
Changing the entire name of your race is a cultural shift…