Because for the majority of people (>50%) living with your parents past the age of high school has a similar theme of repercussions as being home-schooled past preschool. The longer you stay in that situation the longer you have less opportunities to develop the skills that you’re expected to have by the time you hit 25 and those skills are ones your partner in life would want you to have… just like you wouldn’t have as many opportunities to develop the skills your friends would like you have to have if you’re home-schooled past preschool age.

Nevermind all the fun experience you inherently are more likely to miss out on when you live with your parents in your most “free years”