You can't have both "everyone should want to live in the same place" and then also want "everyone should be able to afford to all stay in the same place".
Highly contented areas aren't going to get cheaper even if you double the accommodation. The expensive areas are expensive because people either want to live there or need to live there.
If you reduce the amount of people who need to live there, prices will reduce accordingly.
We need to not cover all decently accessible land on the planet with either sprawl or agriculture. That's bad for the environment.
People need to have affordable access to medium-to-high density housing for reasons of physical and mental and cultural health.
Concentrating people in medium-to-high density housing makes it easier to achieve our decarbonization goals.
We need to work backwards from there. If the market doesn't cooperate, the problem is the market and how it's set up, not the goals.
Physical and mental health is better out of the city than in it.
And cultural health is purely subjective: what on earth makes you think that what you consider good for culture is the same as what everyone else considers good culture.
This is what I meant by attempting to enforce your moral mores on everyone else.
> Concentrating people in medium-to-high density housing makes it easier to achieve our decarbonization goals
Well that's not the problem being discussed here, is it?
We're talking about how to make certain centers more affordable wrt housing.
Removing need is a good first step, as that lets people who want to live elsewhere, live elsewhere.
Market schmarket, the thing not cooperating is people — families. Any plan that operates on the premise that people will be fine and willing to give up detached homes with useful amounts of land is doomed from the start.