I lived at home after college and during and after grad school until I married. Mostly everyone I knew, with a few exceptions, did the same. It’s just what we did.
My kids, two of whom have graduated college and are working in their fields and making good money, also still live at home. Why move out? It’s far cheaper here in NJ to live at home. Two youngest in college still live at home (one lives at school during school year).
One of mine is getting married in September and she and her fiance (who is a physical therapist) still live at home. Why waste money paying rent?
NJ is the worst state for young people to buy homes; our place at the top of the list nationally for property taxes (again) confirms this. Young Americans would rather buy homes in states with more jobs, less taxes, and more Americans.
To compensate for this exodus of Americans, NJ has functioned as a “sanctuary state” for decades now.