It was, like 25 years ago. Well, maybe 15 years ago.
Pre-2007.
Because back then people were making good money out of college, and they were able to buy a house for themselves. Shit, they didn't even need to go to college. As long as you were working hard before 2007, and you were going to be able to find a down payment on a house as long as you didn't have some kind of financial affliction.
That's not to say that gen X had it easy as compared to those before them, but there's a clear separation.
Millennials tried their hardest not to live at home, just because of the social stigma.
Gen Z is feeling that stigma less. That's why you're probably here questioning why it's even a thing. You're probably Gen Z.
I really hope the stigma goes away because unless the world economy improves, a lot of people will have to stay with parents until a lot later in life.
It is a cultural thing though. It's not an issue at all in most of SE Asia.