Combined with a bias in family courts, an acceptance of alternate families (so a reduction in social costs of not marrying), and a rise in the acceptance of divorce. Why marry when you can cohabitate in a state without common law marriage. Having kids is still a challenge because if the couple splits custody still has to be decided, but there are a few options for that as well.

I'm sure that's what he's referring too.

Also the massive increase in hypergamy thanks to the commodification of dating.