Suburbs don’t exist because of some big oil and auto company conspiracy. They exist because they give people an option they find more appealing vs urban areas.
You are certainly welcome to try and lure more people out of the suburbs and rural areas by creating better high density, carless cities. I think the issue is that when people have kids, they want bigger homes, yards, more privacy, lower crime, freedom of movement etc.
It isn’t clear how to give people (in the US) the things that they want and make a city walkable. If it was obvious, there would be plenty of examples.
No, modern car-dependent suburbs actually do exist because of oil and auto conspiracies. There exist options between high density and car-dependency. Surburbs can be walkable, and cities can have walkable low-density areas.
Well, we could stop pretending that God gave cars dominion over the earth and build livable cities.