But then you'll run into traffic/parking issues unless you have a good public transit and land use policy (e.g. bikes, trams, mixed use development, etc). That requires such good design skills few cities have mastered it (Tokyo, Copenhagen, Singapore).

I know it seems this way, but all you have to do is not subsidize driving with government provided parking, and not build highways, and there's no traffic problem, because people don't get cars in the first place - they don't have anywhere to put them and there's no highway to punch through dense neighborhoods. Transit and bike infrastructure can always be built after the fact through public demand. When you let go, the people who WANT to live in high density without cars FLOCK to what gets built.

In fact, if you really stop zoning, there's a decent chance companies will ASK to operate transit for you, because those population densities and no free car competition can make it profitable. This happens in many cities!

Mixed use development happens if you let it happen. Banks and developers like money, and mixed use makes way more money, so they want to build it. Sometimes they fuck up and don't, and those land owners pay the price and retrofit. And that's fine. Again, just let them.

In high engagement Western societies, where people get involved in politics and urban planning, "design" universally leads to car subsidies and shitty outcomes. The market does a way better job.

It really doesn't take that much at all. You just have to allow apartments and mixed use zoning, and not actively chop up the land with stroads.

Human populations naturally gravitate towards walking, and it's pretty much active sabotage of the outside environment that has broken this.