Do you mean as opposed to singles or to extended families? In either case, I'd be interested in a source.
Do you mean as opposed to singles or to extended families? In either case, I'd be interested in a source.
https://en.wikipedia.org/wiki/Poverty_in_the_United_States#P...
https://www.ssa.gov/retirementpolicy/fact-sheets/marital-sta...
Marriage is mostly a "capital" redistribution system and with strong public services (ie shared services) there is much less need to focus on the nuclear family as a protection (sharing of ressources) network.
Ex. When a few years back pension laws changed in Japan and housewives got the right to get a pension separately from their husband, the rate of divorce boomed.
There is nothing in the nuclear family that makes in a natural fit to what humans are as social animals.