There are plenty of dense cities around the world where I'm sure the owners of apartments in the (walkable) center would have enough money to buy a house/McMans

There are plenty of dense cities around the world where I'm sure the owners of apartments in the (walkable) center would have enough money to buy a house/McMansion in a nice suburb. And some do. But plenty don't. And building dense walkable cities with nice public transportation works very well and does not make these cities less attractive as far as I can tell.