This is the root of it, and something most on HN won't accept. Optimistic people generally see and seek opportunity (either knowingly or unknowingly) more frequently than pessimists.
Won't accept? It seems startups are the same. "Rationally" a poor way to get rich, but if enough people miscaulate their odds (or enjoy it for nonmonetary reasons) we'll get a few big successes.
Most millionaires are those who started their own businesses or are self employed. Certainly not SV unicorns, but they run businesses you've never heard of started by ordinary people.
Yeah, there is that thing when optimism becomes euphemism for naive, not allowed to talk about problems and disadvantages. But I think that is manipulative way to see optimism.
Sometimes chances are low or times are bad and optimism should not equal refusing to see that.