Pessimism gets treated like intelligence. Optimism gets treated like a defect you grow out of.
Act like improvement is impossible and you stop trying. Then nothing improves, and you get to feel right about it.
Optimism is work you practice, or you guarantee the outcome you claim you were only predicting.
You're not an idiot for believing things can get better.
https://www.joanwestenberg.com/p/you-are-not-an-idiot-for-believing
There is also a wisdom to tell the possible-even-if-hard from the actually-impossible apart. And people tend to err towards either side of the balance.