It's like having a convenience store in the lobby of an apartment building. Seems like a great idea, but it takes a huge apartment building, or a city block of modest ones, to support a convenience store. Vending machines, maybe. We see this with all those "mixed use" buildings going up in Silicon Valley, with retail spaces on the ground floor. It's really hard to fill those retail spaces.
The problem is that all of those places are planned. I get major 'Soviet Central Planning' vibes from the USA when it comes to zoning and planning out cities. Of course the people making the decisions on planning have no idea what will work. They only know what will work in the most rudimentary, scaled up, sense. Small shops need to be allowed everywhere, rules about minimum parking, lot sizes, use, etc need to be re…
That sounds hyperbolic, but the first suburb in post-war US was a planned whites-only community to escape the city. (Levittown)
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With that said, yes, the US purposefully planned blocks of cities to be dedicated to one purpose. This promotes car culture which, surprise surprise, car and oil companies were big into lobbying to shut down mixed use and public transit, and continue to be.
Mixed use areas are typically either big cities, have pre-war origins where it has basically always been mixed use or typically both.