I know they are exceptions to the rule.
When I growing up in the 1970s, it was still considered unmanly to live with your parents past 18 - or past the time you got out of college. That's what drove me to get out. I joined the military at 18 and never went home again. For a couple years after my discharge, I lived in a ratty apartment. and ate a lot of Kraft & Macaroni cheese (5 boxes for a dollar!). Drove around a beat up AMC Pacer that smelled like gas. But I had my own life and quickly improved upon it. Now I have an upper middle-class lifestyle that I earned all on my own dime.
I've heard the arguments pro and con but I'm convinced that adult children living at home is a bad idea for all involved. It robs the children of ambition and decreases their chances of even marrying well. What fine woman wants to marry an overgrown kid who dresses like a slob, plays Nintendo games and participates in fantasy sports leagues while his mother makes his bed for him in the morning and does his laundry?
I also meant to add that for the parents, it robs them of a much deserved period of their life when they should be re-discovering their marriage, going on vacations together (that don’t involve amusement parks), and maybe down-scaling to a smaller home instead of still making beds, doing laundry and worrying about where their overgrown children are when they aren’t there at 2 in the morning.