Moreso in many European countries where the per capita birth rate has plummeted. When the average female is only producing 1.2 children (several European countries), an aging society and small families are guaranteed. Makes this sort of multi-generational approach not only feasible, but necessary.
Not sure it is linked... Britain, and northern european countries, have pretty low birthrates, yet children move out. Southern european countries have higher birthrates, but those extended households are more common there. And in countries that stand in the middle (France is one), you'll find more of those multi-generation families in the same communities where you have higher birthrates (immigrants, catholics, periurban/rural).
I believe this shows how rural our societies are. In Southern Europe (including France), most of the population was still rural a few generations ago, and such extended families are a hallmark of rural societies. This probably results from the way inheritance worked here. In many southern countries, the land was split between all surviving children, keeping everyone in the farm, and then around the farm. Northern societies kept the land whole by designating one heir (elder/son, chasing the others into the cities, and splitting the families. You can also see the result in the countryside: lots of small fields, with hedges in between, aka bocage.
< Message edited by fcharton -- 12/31/2012 9:35:50 AM >