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

[Kyohei]

The souls in Zodiark weren't consumed and we free them in Endwlaker. Hydaelyn had less people so they had to use even their soul aether to fuel the summoning. At the end of Anamnesis Anyder, the records say that none of Hydaelyn's summoners survived. The soul consuming Hydaelyn was even confirmed by Yoshida saying Venat's very own soul was consumed, and that is why she isn't returning to the star.

They weren't stubborn, they had no other solutions to go by for lack of knowledge on the situation and lack of time to study it.
Emet-Selch specifically said he didn't believe the WoL's story of the future but he accepted the idea of dynamis and was only shocked no one told him before. Also, even if he didn't believe us he still wished to investigate more in the end, and he believed in Venat. No valid reason to write that he wouldn't a second time, especially knowing there was something wrong with his memory.

Even if she did tell others, it wasn't to stop Zodiark's summoning as it was part of her plan. Informing the whole civilisation about dynamis and the upcoming Final Days could've changed everything. Venat wasn't a nobody, she was highly regarded by the ancient society. Even if some didn't believe her, others would've investigated dynamis. Yet she did not, and her civilisation was unprepared. Even if they didn't believe her at first, when seeing the first signs they would've understood. An understanding of the situation would've lead to other measures.