The math isn't hard. After two generations of one-baby families, the kids of your kids will have no sisters or brothers, and no cousins, either. And no uncles and no aunts either.
Big Government and Big Data are the new ties that bind. They will grow and not shrink and so will the dependency on support from strangers who don't love you. Politics is grooving to the left, fueled by demographics.
I don't see "The Waltons" or "Cheaper By The Dozen" making a comeback, but with pink-tinted glasses, I see networks forming through social media, networks that meet needs kin groups used to meet, networks that leapfrog right over Big Government and make such top down governance a teentsy bit obsolete.