our society(s) have conducted two (three?) experiments at once, and it's not easy to separate the confounding factors. We spend less time with our relatives. We have drastically smaller families/fewer relatives. We move great distances and go out of touch with not only our families, but also our former friends.

We also more drastically sort ourselves than before by some notions of class like "what you majored in" at "what tier of institution" and "stayed in academia" or "went into industry" etc.

moving to live near friends is probably helpful but not a panacea; nor are we going to do it so...