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

[Rulakir]

The new life is part of it, just not the sole reason.

Venat: "To try and reclaim those lives we lost by sacrificing yet more isn't wisdom. It is weakness. No paradise is without its shadows. If we cannot accept this truth and learn from our pain, then our plight shall be repeated."

I'd forgotten about that, thanks for reminding me. I hated that cutscene, so I've tried not to watch it any more than necessary.

It doesn't seem likely that they're going to debate entrusting the world to flora and fauna. Like you said, they would sacrifice without hesitation. But what would give pause? New people.

You've given me something to think about now. I generally don't like to debate the third sacrifice due to lack of information. I don't know what other races existed that weren't Ancient constructs. I don't know if the Ancients would have sacrificed themselves to bring back other races either, it seems like a damned if you do and damned if you don't scenario. Either they were so altruistic they did so, or they were so selfish they did not. I'd only been thinking in terms of making the star inhabitable again, in which case it wouldn't make sense to bother with anything more than the basics needed to replenish and sustain life.

My opinion is it still never should've gotten to that point. Venat wasted valuable time they could've used to prepare for the Final Days. Instead, it hit without warning and by the time they figured out how to stop it they had no choice but to use themselves as primal fodder (something she didn't attempt to stop either). I can't imagine knowing what she did and not informing anyone in a position to do something about it, it's unconscionable to me.

Also....why sacrifice at all? Their people are lost. It's very sad. Move on. Humanity learned how to do this after the Sundering. They couldn't.

Either you've never lost anyone or handled it much differently than most people. Humanity didn't learn anything. The 8UC timeline suffered far less than the Final Days and still labored for two centuries to undo it with the belief that in doing so their existence would be erased. Post sundering and 12k years into the future, people were still willing to sacrifice themselves to return to the past over moving forward. Had current Etheirys suffered the Final Days more substantially I've no doubt they would've ended up the same as well.