I live in a top 10 US city (based on population), and it seems to be as you describe - generations of family living nearby, grandparents, etc. always around to help with the kids. Weekly (at least) family meals, parties where the whole neighborhood is invited, etc. I grew up knowing most of my friends' cousins and grandparents because they were just always around. Even today, I know my neighbors' kids and nephews because they live close by, too.