Urban housing needs have been the same for generations. A child is brought up in a family home and stays in it until marriage, when he/she starts a new family in a new family home.
Things have changed. Young adults go to college and live in shared accommodation. On graduation they sometimes move back home, but often they carry on with shared accommodation, sometimes for many years. My son is over 30 and has lived in halls of residence or house shares since he was 18. I know a lot of young people in their 20s and 30s who have been in live-in relationships but had to get out. "I felt suffocated. I needed my own space" is a common explanation.
There's a new breed of people, unwilling to compromise their personal freedom. And there are a LOT of them. Mostly they're living in house-shares, often not getting on too well with their housemates. Or they're living quite alone and hating it.
What we need is a Hall of Residence for adults. Something like individual bedsits with minimum cooking facilities (refrigerator, kettle, microwave), minimum bathroom (washbasin, WC, shower), with communal lounge, kitchen, bathroom facilities. They get their own space, but they also get to feel part of a community. They can cook and eat in their room, or do something adventurous in the main kitchen, for themselves or for the group. They can choose what they want to watch on their own TV or go to the lounge and watch sport or Dr Who or whatever in company - some TV is
much better watched in company!
It makes sense to me, so why aren't developers building them?