Here is My Contrarian view.
Virtually all my Boomer Friends have their Kids and grand Kids living at home , and NOT because they “WANT TO”, but because they “HAVE TO”, Others who are living away even have Jobs that would allow for them to PAY for a mortgage but cannot “GET” a mortgage because of the tighter lending standards now, (really if ever there was a time for looser lending standards in most areas in the US. not Coastal SD really, “NOW IS THE TIME” not back in 2004-6).
I think once the ball gets rolling it will pick up speed a lot faster than most think.
But that is just my opinion .
Oh and I did live in a Van for about two months once. (spend most of the time by the beach so not bad really, you can get away with that when you are young).