The Elemental Lords were bound to the Elemental Planes thus severing them from Azeroth’s World Soul so that she would not revive them so when the Primal Incarnates arose they practically for all intents and purposes became the replacement avatars of Azeroth’s 4 Elements.
Severed from the World Soul the Elemental Lords are much weaker than they once were so the Primal Incarnates are the top Elementals of Azeroth not the Elemental Lords who are mere shadows of what they once were.
We are basically facing the 4 successors of the Elemental Lords!
Guess what I want to know is what makes these elemental dragons any different from the Elemental lords we fought back in Cata. Both appear to have been sealed away, Both seem to control the elements, Both are being released by crazy cultits/night elves angry with horde. Both have ties back to old gods.
It’s probably because right after that happened, a hole ripped open in the sky, the dead walked among the living, a Zovaal happened and wanted to suck Azeroth, and then suddenly dragons.
I think it’s mostly the dragons. It is hard to be very concerned about a missing firelord when your entire city and the rest of the world is stuffed full of lazer breathing dragons killing your framerate.
All of the incarnates are evil. Only 2 of the elemental lords were. Those being Ragnaros and Al’Akir. For the other two. One of them was angry that we killed her only daughter but we earned her trust via her sons and the other fought a giant squid off screen cause blizzard cut a raid.
Maybe the dragons were the original elemental lords before the Titans took control, and after the dragons were altered, the other elementals had a civil war for dominance of the planes. Elementals don’t really die (I think), so like the Burning Crusade, they were always gonna come back for a rematch. Or, the ending of Cataclysm was such a disappointment they decided to try and rectify the mistakes.
None of that is necessarily concrete canon & is all mere speculation, some interlinked with a few merits of the truth …
The Elemental Lords were bound to Azeroth itself & thus the keepers knew that they could not utterly destroy the beings. The spirits of the elementals were bound to Azeroth itself, yes – so if they were killed, their corporeal forms would simply manifest again in time.
Ra found the solution of setting out to imprison the elementals, much as Sargeras had done to demons. Ra, with the aid of the titan-forged sorceress Helya worked together in concert to craft four interlinked domains within a pocket dimension known as ‘The Elemental Plane’. Ra and Helya then banished the elemental lords and nearly all of their servants to these enchanted prison realms.
SOURCE:Chronicles Volume I, page 32
As for the primal ‘Incarnates’ -
The originated proto-dragons species that began to form over the world had a wide array of strengths and abilities. Some were gigantic winged beings of incredible fortitude, their spirits tied to the world itself(Not necessarily specified the world soul).
However the line that I’d wager would be the golden goose answer, from Chronicles would be —
‘Others had unknowingly tapped into the latent elemental energies that permeated the newly ordered world.’
SOURCE:Chronicles volume I, page 42
As per the above, I’d wager:
After the elemental lords were imprisoned they weren’t able to absorb, attain or lay claim to the stated ‘latent elemental energies’ and thus the Primal Incarnates rose forth.
That being connected to the elements, aside from giving them a connection to the world they’re on (and maybe also the world soul, but I wouldn’t state that’s the reason for the magnitude of their power) would also give them a link to the elemental plane.
Due to the stronger connection to the elemental plane, would also help explain why they’re not all against each-other (Remember the titans created pocket realms for each major element WITHIN the elemental plane that had already existed).
I’d say the laying claim to elemental latent energies after subduing the elemental lords that vied for its claim, along with the old gods that waged war with one other for it being toppled – The energies & power were united in the rise of dragons, those that had ties to the world and perhaps to some merit - the world soul also, could had gained even further power too.
— All this said, shared, discussed and speculated – we might get some more lore on ‘The Incarnates’ to shed further light on these matters ~ throughout Dragonflight!
The power they represent can never be destroyed, but the actual individual can be. And they can only be killed when inside their elemental plane. It is why we haven’t seen Al’Akir since his death in Cata. As he was killed in the Skywall. Hence why Thunderaan was able to become the elemental Lord of Wind following his resurrection.
However it seems that a previous elemental lord can be brought back to life. As seen with the Cult of Ragnaros trying to bring him back.
Cenarius yells: Ragnaros has perished. But the primal powers he represents can never be vanquished. Another will rise to power, someday. - https://wowpedia.fandom.com/wiki/Ragnaros_(Firelands_tactics)#Quotes