As a recent college-grad who'd moved to suburbia, I think the automobile-centric culture in America is what is killing intimacy. If you were not able to make close friends in college/early-life, than once you live on your own in the suburbs, it often feels impossible to get any sense of intimacy. Intimacy is built up with small moments, and when every interaction has to be a commute-laden ordeal, you lose the opportunity for spontaneous and random social interactions, making the process of building of relationships orders of magnitude slower.