I've been poor as a church mouse. And I've been pulling down 6 figures. Money doesn't buy happiness. But it also does, to a certain point, if that makes sense.
A person can't really be happy or do a lot to change things when they're hungry and terrified of homelessness. We focus on the immediate. It's natural. Basic needs will always take precedence. Beyond that, money doesn't make one happy, but to that point, best believe, it does.