The people who are homeless on the streets in USA are very visible. In average third world country most would be dead or confined because they don't play silly games with junkies and crazies there, so there would appear to be less.If they are doing so well, why does the USA have so many homeless people?
There might be lots of wealth, but if it's all going into only a few people's pockets, that's not healthy.
USA does have a plague of free roaming junkies and unconfined crazies, not a poverty driven homelessness problem, those are a tiny fraction of the homeless and one easiest to fix by usual measures.