People who get rich by accident (e.g. lottery winners) typically spend it all and end up back where they started. Money is hard to hold on to for people who are unsophisticated about money. Predators and grifters come out of the woodwork to take a lot of it, and the rest gets frittered away on trinkets.

I wonder what is better, for people, for society, having many rich angry people or having many poor angry people?

Nailed it.