Aldmeris very much exists - and the Elves are dying for a reason
Many and most people agree that Aldmeris doesn't exist. That it's just a metaphor for the origins of the collective elven race. I do not believe so. Aldmeris exists, but it may currently in a different plane of reality. It may well be the Elven Afterlife, based in Aetherius. Here's an explanation of why:
Auriel was disgusted with his creation, he sees it as his only moment of weakness. So, the Sun God waged war with Lorkhan in the ehlnofey wars against Lorkhan and his armies, who would go on to be man. Trinimac, Auriel's Greatest and most popular follower, defeated Lorkhan. It was after this, and convention, that Auriel ascended to the heavens in plane sight, so that his people may know to do the same. And indeed, they are learning.
Think about all of the conflicts in the history of Tamriel. So many of them, in fact nearly all, have been lost by the elves. And indeed, these wars have often lead to the complete and total eradication of these races. The Snow Elves - so many died, and the rest changed forever. The Ayleids were eventually destroyed completely, with the rest dying out naturally. Even the Dwemer, who had no love for Auriel, found their own way to ascend to a heaven like nature. Why would Auriel, who's so determined to care for the souls which he subjected to lives of mortality, allow his people to be wiped out, to lose so many wars and conflicts? And why would he allow them to go to the dreamsleeve, where they would be forced to live a mortal life all over again, this time not even as a superior elf (possibly)?
It doesn't make any sense without an afterlife. Auriel wanted them to ascend to the heavens, there has to be an elven afterlife, as far as I'm concerned. Aldmeris is that afterlife, Aldmeris is the heaven all elves aspire for.
Did the Continent exist? I believe so. As the Aldmer left to escape from the great "threat" emerging in Aldmeris, they headed to Tamriel. They headed straight to man, and the wars that would emerge from such encounters. And without Auriel's help, they would die. And so, Aldmeris would be reached. The reason it was taken in the first place is quite simple. The Elves needed their heaven, and Aldmeris, and all it stood for, was perfect. A wasted idea, a wasted potential, where mortal boundaries still existed.
Now, the only issue is, that Auriel ascended so that they could learn to ascend like him. For this there are two possibilities.
This supposed message was misinterpreted by the Elves, and thus they believe Auriel simply wanted them to reach heaven.
Many elves claim ancestry from Auriel itself. When Auriel achieved Dracochrysalis, he joined with the Aka Oversoul and went from Mortal to Divne once again. The elves genuinely have ancestry because of the forces of Mythopoeia, and so, have a significant link to the Aka oversoul themselves, a link that will grow as they come to closer to Auriel and death, and are freed by physical limitations as their spirits are freed.
The idea of an ascended continent provides a link between the immortal and mortal planes, a link that allows them to ascend.
So, we've looked at the how, and a bit of the why, but let's look at another point. In Sovngarde, Shor is gathering an army of the greatest warriors faithful to him, for the great battle at the end of time. Considering it was a Battle of those who would become elf and those who would become man that kicked off time properly, and caused the event of convention to take place, is it not reasonable to assume that a War of Man and Mer may be exactly what ends this world, and Auriel himself is building an army?
With regards to the Dwemer, who ascended in a very different way, I have two ideas.
They foresaw their destruction so Auriel could claim them, and so used Numidium as not just a means of escaping Nirn, but of escaping the Gods themselves.
The Numidium only took their soul energies, whilst their personalities were maintained and sent to Aldmeris, perhaps being powered by the Souls of the fallen enemies of Auriel.
What do you guys think? Apologies for the poor quality of writing, as I'm in a hurry to get this out :D A lot could be added to this theory, and a lot could probably be argued against. What are your thoughts? :)