I agree. However, I always got the impression that when people said poor people were happy they were referring to, say, tribesmen in the bush, rather than people on the streets of a US city. Not that that makes it any better, but the things required to be middle-class in one society are not the same as the things required to be middle-class in another society.

I think part of the reason that people who are more well-off cling to the "money doesn't buy happiness" saying is because they are perhaps not happy with what they have, but they know that more money would not make them any happier. On the other hand, having enough money to not have to work seems like it would make anybody happy.