What it sounds like you are saying is that it can, in the right circumstances, create a feedback loop in either direction. And you are right. With that said,

What it sounds like you are saying is that it can, in the right circumstances, create a feedback loop in either direction. And you are right. With that said, Nico had an excellent point. For most people their friends will include a peer group that almost certainly makes similar incomes to theirs, and for most people you will only really start making a lot of friends at a higher socio-economic point on the ladder when you move up to (or are in the process of moving up to) that same higher point yourself.