Endwalker's message (spoilers!)

[Lauront]

I don't think that was what was being portrayed, given that the Dragons were said to have a peaceful society only to lose it to an outside invader through no fault of their own. Furthermore, the Ancients devoted their efforts to the benefit of the Star itself.

Even if it were meant to mirror ancient Etheirys, I don't think it's a convincing line of reasoning that it was its inevitable future. Why? Because the ancients were not ultimately given this knowledge to reflect upon and consider whether adjustments to their society were necessary as a result. Again, the scene we're shown is Venat just walking up to a crowd and offering platitudes as the star is dying. Why should anyone take her words seriously at that point? As you say, the dragons did have a paradise of their own, which was robbed from them. The ancients were never given an opportunity on that front. So that whole dungeon scene is easy for me to take as "this looks like that, so it must be the same" attempt and shrug it off with a "meh". Very pretty area, all the same.

My view is that they're trying to resolve the plot in the limited time they've got, want to reconcile the aims of the remaining Ascians/ancients with those of the sundered and Hydaelyn, and obviously did not want to create a different world to what we already have now (or we'd be looking at another ARR scenario), thus they chose this route, where they were all given knowledge that rebirth in the Aetherial Sea would eventually restore, and which they did not have in the original timeline - Venat herself included. The unfortunate side effect is it just comes across as very forced, messy, full of logical holes and unsatisfactory to many of us. There were other issues I had with the plot pacing and writing but that was by far and way the main one. So I guess they would rather we don't look too closely at it and take it for what it is.