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

[Pyro2hell3]

The Final Days did not wipe out the Ancients. It decimated them, certainly, though there were enough survivors to work at preventing Etheirys from being destroyed by summoning Zodiark to serve as a barrier against the return of the Final Days and also restore life to the planet.

It was Venat who wiped out the Ancients through the horrific act of genocide that was the Sundering.

This does raise a very important question. What exactly happened when Venat sundered the world? Did all the current inhabitants just pop out of existence or something? Did it cause 14 umbral calamities at once or was it a normal day?

[TaleraRistain]

This does raise a very important question. What exactly happened when Venat sundered the world? Did all the current inhabitants just pop out of existence or something? Did it cause 14 umbral calamities at once or was it a normal day?

If I remember, Emet explained that outside Amaurot in ShB. When a soul is sundered, a copy (a reflection) of the being is created but it doesn't have the same memories. I'd have to look at that cutscene again, but I never got the impression it was wiping anything out of existence.