So I remember the scenario with the voidelves quite differently.
The blood elves were portrayed as objectively right, only the voidelves naturally do not see themselves as “wrong” in the self-image, Umbrics group was even called extremists, they believe fanatically in their idea, regardless of the cost.
The voidelves see themselves as betrayed, and the voidelves say it was not wrong, that does not change the fact that the blood elves were objectively correct in their assumption that the void was a danger to the well.
The narrative does only one thing here, on the one hand it represents the objectively right, and on the other hand it lets the voidelves “speak” as they themselves feel it, thus it seems - if you don’t look at the context - that the voidelves are also represented as right, which here however only represents subjective statements of voidelf characters.
We are still talking about the Kalimdor Horde and Kalimdor Alliance.
In the Ek`s: Yes, there is a reason, but what reason would the night elves have to participate there? or even to attack the Horde, nothing would have happened on Kalimdor for the time being, nothing would have changed. The only thing that changed, the only form of “concession” that the Kalimdor Alliance made to the EC Alliance, was the signal of solidarity was to end the trade deal. Which in turn would have put Garrosh on the spot and he attacked again.
Just for the record, the Alliance did not have a High King at the time, so it would not have been a declaration of war by the ALLIANCE, but a declaration of war by Stormwind-an Alliance nation-to the Horde. The others were even against it, and did not want a war.
By the way, this truce - about which you complain here - which was decided between start -WOTLK and start-Cata, was necessary, because otherwise it would not have been possible to defeat the Lich King. Wrathgate and the consequences of it were at the very beginning of WOTLK.
The tournament, Ulduar, Icecrown, all that came later, and needed a truce.
Definitely already more complicated, and would be a reason for war, however, it reveals then unfortunately what Sylvanas really had in mind with the Val’Kyrs, Odyn, the slavery, it saw also the Horde hero that she plays here there 4d Cheese, and it is something larger, what happens here. So not exactly a good motivator if it turns out the other side was right with their damn guess all along and Sylvanas was already back to her shady games here. But in the end it would have been a reason for war.
Bilgerwater and the spything, i thought we had argued about that in the past? 
I think you’re exaggerating a bit here, as well as with the statement that they don’t learn and always stay in the status quo. The night elves have always adapted and refined their approach to enemies, it’s not like they use the same strategy against demons as they do against orcs/hordes.
What is true, however, is that technologically they do not take the step, but the narrative also shows that they do not have to. They can easily beat any technical machine with magic(Which, by the way, is also a strength of theirs: magic
), even let it sink into the ground, that’s what the narrative shows. But from BFA - as a small point of light at the end of the tunnel - a closer cooperation between Shen’Dralar - Druids - and Moon Priests could emerge. That would be a real advancement, because as of now the mages are more of a sideline, and very little used.
And generally speaking, no one, no race, can ever reach the peak of 10,000 years ago again, we live in a post-zenith scenario. The peak of Azeroth’s civilization in general was 10,000 years ago, this has been passed.
The night elves lost their peak
The Titanforged lost their peak
The Trolls lost their Peak
Now they try to make the best of it.
