You can only fit so many real houses in a given area, after which you're building high density housing and a lot of (I'd even argue most) people don't want to l

You can only fit so many real houses in a given area, after which you're building high density housing and a lot of (I'd even argue most) people don't want to live in. Public transport is key, especially trains that can bypass traffic at high speeds. In my city in Australia I live about 25km out from the CBD, but I can get there in under 30 minutes via train if I ever need to - it works very well and I don't have to live in a tiny shoebox on top of 100 other people.