> I suspect that has as much to do with the culture of honor/not being a dick as it does with mixed use zoning.

Yes true, and many people gloss over the issue of lawsuits - the US has a "lawsuit happy" culture that make many things very expensive.

I think that takes too negative of a approach. It is simply a cultural difference. I think about China, most of the cities have pretty lax zoning...to be fair I don't know their exact regulations but its quite normal to have business in the first floor, your home above it. But people there do not generally care about personal space, same with Vietnam, nobody cares there is a welding shop right next to their house.

In the US there is generally a large desire to have a garage and some space away from your neighbors.

On top of cultural differences, I think itsj ust really hard to change existing cities without massive forces pushing it. You almost have to start fresh and even then you need a level of collaboration that is hard to get. I do think there is some change happening, I have seen new communities in Texas being build where there is central playgrounds and coffee shops being built as part of the development.