What's the point with that quite lackluster story in Endwalker?

[KizuyaKatogami]

Civilizational fuck ups rarely result in the end of the world though, and the Ancients were uniquely qualified to do that.

It happened in the 8UC though with black rose. So it seems very possible. Look at the war of the magi as well. Major catastrophic events that could have or did potentially end the world. It really isn’t as rare as you might think, especially in a world where magic exists.