>>717330521
With zero actual, tangible evidence.
The idea that the world will die is literal conjecture. They didn't really attempt to save the world either because our Marchlet is way too biased against fantasy.
Even if it did, for the sake of the argument, the world could have been reborn into a new fantasy world with all the people in it. No one knows anything about new Ivalice, but they jump to crazy conclusions and confirmation biases.
A dream you witness alone is just weightless fantasy, a dream you share with others is indistinguishable from reality.