There's an opposite political argument that the decline of the family, especially among the poor, was due to government benefits replacing the need to maintain social networks and interdependent families. In the 1800s and early 1900s, at the height of the industrial revolution and in the absence of any welfare state, poor Americans of every ethnicity had incredibly close-knit communities and extended families.

Life was harder, but you could lean on friends, family, and congregation. That's where the classic trope of rich people being lonely and surrounded by fake acquaintances while poor people have authentic community comes from. Maybe now that every level of society is relatively richer we're all that much lonelier.

Seems unlikely: why do staunch conservatives reproduce far better than liberals?