If we're interpreting Hythlodaeus himself describing their situation as a "purgatory," and a people whose culture puts a premium on their connection to the star and returning to it in death, being cut off from the cycle of the star not therefore equating to "a fate worse than death" might also have to go into the "that is incomprehensibly mind-boggling to me but I mean uh if you say so" category.
But the constant citation of "Hythlodaeus seemed ok" is... extremely Something. Meanwhile, the other souls are known as "Anguished Spirit," "Forlorn Spirit," and other such cheerful monikers in this zone literally named "The Sea of Sorrow."
Uh, yeah, definitely seems perfectly all right to me! But yes, Hythlodaeus, a remarkable individual, is relatively coherent. So if I find one person who seems relatively okay in objectively terrible conditions, it means everyone involved is definitely okay in those same conditions, right? We don't have to worry about any of them! (This is not how that works, for what it's worth.)"I... I...
Return... I must...return...
Why... Why... Why!?"
The vision's grief takes form and lashes out!
"Home... I want... I need..."
Yeah, I'd say that's what "the planet was completely dead to the point that nature did not function and the wind ceased to blow" would indicate. You do remember how even a mostly-forestalled Calamity like Bahamut caused massive corruption in massive amounts of aether, right?So there were no crystals? No other sources of aether at all? And the Ascians, when sacrificing those on the Source, are just doing it out of spite?
As people have indicated, it only makes sense that if the Ancients had alternatives to sacrificing their loved ones, they would have done it - and their actions and intentions follow coherently from that. Finding an alternative was what they were planning to do when they had breathing room with the world not literally ending around them, and they could harness other resources. Venat's actions, however, were fundamentally driven by an ideology of "let there be no turning back" and a primary concern with the actions and mindset of the sacrificers, so the precise content of the sacrifices used as the means to do so aren't necessarily as relevant to her.