I've heard American universities do a lot more hand holding than their European counterparts (not sure how this manifests). When I went to uni (and left home) it definitely helped me mature - I had to worry about cleaning, buying groceries, feeding myself, doing laundry, etc.
I also had the freedom of nobody knowing or caring where I went and how late I came home (=greater responsibility for planning my time).
But I understand what you mean - i had a childhood friend who went to a 2 years vocational school after highschool (during which he lived at home) and then enlisted in the army for 4-5 years (in a non-combat technical role). I suspect the army basically takes care of you when you live on base because afterwards he moved back home & I got the feeling he pretty much stayed stuck in a child role for years later (may be complicated by mental health issues).
I think never having had to really be completely responsible for himself held him back.