Come to think of it, the strongest community I can remember was in married student housing at college. The apartments formed a ring around playgrounds for the kids and the parents came out to tend them. We were all poor, around the same age, with the same struggles (passing our classes). The rich in Silicon Valley often choose neighborhoods in the hills set back in the trees to get privacy. They may get loneliness as part of a package deal.
There are some fascinating studies about the design of public spaces and sense of community.
It's from here: