Livre d'Or

I am not a demographic historian but I know a bit about that area, and the whole 'marrying relatively late and setting up independent household' model goes back at least to the Middle Ages in North Western Europe, or at least parts of it. What this also meant was that couples were largely of an age (rather than much older men marrying much younger women) and families smaller, which had some rather positive knock-on effects for women.

However, I think one can exaggerate the nuclearity of this model and how much it was far more complex in practice. Families still tended to live close together even if not in the same house, and I think it is in that famous study of kinship in the East End in the mid-C20th in which the continuing close warm mother-daughter ties were mentioned - 'always popping round'.

I myself grew up in a 3 generation household (my mother's parents, my parents, myself and siblings). At one point my father's elderly mother was living in the granny flat next door. My sister and brother-in-law still live in the same house with my father living in the granny flat. Two of their children live very close, and the other just the other side of town, and there's a fair amount of popping round. But they all get on. It's not a universal solution just because it works for them. And it's also very dependent on a whole range of other factors, like the housing situation - the kinship study I mentioned pointed out the adverse effects of people moving out into lovely new towns from their bomb-damaged slums but losing the ease of contact.