I disagree about the "rent money is wasted money". Renting gives you independence and flexibility. I didn't have the option living at home as an adult but even if I did, I would have hated it. Independence was everything to me, can't imagine leading my own adult life when my DP sleep in the next room.
I dated a lot throughout my 20's and never met a guy who still lived with his parents.
I never spent "thousands" a month either, all my houseshares in London were £250-£400 per month. But I was quite canny at finding the really cheap places
. They of course weren't in trendy parts, most in zone 4 and not near a tube. But hadn't I done the housesharing in my 20's, I feel like I would have really missed out. I met so many different kind of people, some were loons, some have become friends for life. I also had a chance to live in some interesting properties which I would have never been able to buy.
It may be sensible and comfortable to stay at home but IMO young people do miss out.