I agree with you. I think it was my father's generation (he would be 83 if still alive) when people started to frown down upon adult children living at home and stigmatizing the practice.
My uncle made a detailed genealogy of my family and there was always at least one child who stayed and lived with their parents, sometimes married, sometimes not, but always at least one. It was how houses were passed from generation to generation. Most of other children seemed to always live near by. If not on the same block, then usually within a couple of streets. One or two might move further afield, but most stayed near by, unless there was a famine or another tragedy. Those stories ended with my father's generation.

I find it funny that we revere family farms; farms that have been in the family for umpteen generations, yet the reason those farms stay in the family is because at least one of the children stayed at home. It's nostalgic, something to be proud of, it's 'murica! Yet those same people will call you a neck-bearded mamma's boy if you're not out of the house by 18 or at least as soon as you are out of college. Cognitive dissidence at it's finest.

Thanks for expressing your thoughts on this matter. Keep up the good work.