Endwalker's message (spoilers!)

[Zukkii]

What a lot of people in this thread fail to realize, is that Venat's actions were the only ones who would break the cycle of the Final Days. Had the Ancients been successful in recreating their paradise, they would cause the Final Days again.

The reason why this would happen, is because they did not understood plight, suffering, and despair. They were all akin to gods in their own right, and they only knew of paradise. Emet-Selch's responses to Hermes proves that they wouldn't learn. In short, the Ancients seemingly perfections would obstruct them from learning about life's imperfections. Venat knew that this would happen, as she was already more enlightened than most of the other Ancients.

If Venat would tell the Convocation, then the only people who would be able to fix the problem would be unmade. Mankind of the future was the only one who would be able to deal with it, BECAUSE they suffer. They would be best equipped with dealing with it, because they found joy and meaning in the small happy moments. They basically spelled this part out within the story too, so I know not how it was missed.

Oh, and if Venat would tell the Convocation, she would become a pariah immediately. Place yourself in one of the members of the Convocation's seat, and think about how you would respond.
The woman who refuses to return to the star because "she feels she has yet another purpose" says that the end of the world is coming, and the people who were present were Emet-Selch and Hythlodaeus but their memories are wiped.

Anyone remember Harold Camping and how everyone treated him like a fool and disillusioned old man? That's what would happen to Venat.