I think a lot of the headaches could be avoided by zoning in ways that allow for density improvements to occur. We can't just build every new city as a planned green city too (i.e. Masdar City).
I think it would be beneficial if there was some kind of standard at a state level for not just building codes but zone codes. It would also be nice if there was some kind of zoning and code for underground, so lower levels could be built as density increased (i.e. Lower Wacker in Chicago[0]) to allow vehicles to still park and travel but allow the buildings to narrow on the upper street. It would then also provide a separation of humans and cars which would help for safety. [2]
That also would allow for the potential building of middle-ground assets that are much more affordable like the Downtown Seattle Transit Tunnel to allow for BRT/Light Rail. [1]
American cities don't like to mix commercial and residential zoning. If you had a mix, you'd see more places with grocery stores you could walk to, like in London or Chicago.
I'm not sure which cities your referring too but even in towns like where my Dad grew up, a population of 40k, they're beginning to zone mix-use in urban areas.
As yardie mentioned, there is a huge demand for mix-use properties. To keep with Chicago as an example, I lived near a large area of small mutli-family (Du/Quad-plex or multi-story flats) and large single-family homes. There was plenty of commercial space but there was a huge local demand for mix-use property which led to it being developed. Called "New City" it was a tower on top of a movie theatre, a grocery store, with surrounding retail and restaurants.[0]
I wouldn't be surprised to see more zoning like that in small to medium cities, however, it's likely they would be more like landscrapers than skyscrapers.
They don't like to but they are doing it now. They have no choice as a younger demographic is clamoring for it and developers are responding by getting zoning for it. If a city isn't planning with mixed use, mid/high density housing in mind then I'm not sure I'd call them a city.
I think it would be beneficial if there was some kind of standard at a state level for not just building codes but zone codes. It would also be nice if there was some kind of zoning and code for underground, so lower levels could be built as density increased (i.e. Lower Wacker in Chicago[0]) to allow vehicles to still park and travel but allow the buildings to narrow on the upper street. It would then also provide a separation of humans and cars which would help for safety. [2]
That also would allow for the potential building of middle-ground assets that are much more affordable like the Downtown Seattle Transit Tunnel to allow for BRT/Light Rail. [1]
[0] https://en.wikipedia.org/wiki/Multilevel_streets_in_Chicago and https://en.wikipedia.org/wiki/Wacker_Drive
[1] https://en.wikipedia.org/wiki/Downtown_Seattle_Transit_Tunne...
[2] https://en.wikipedia.org/wiki/Transit-oriented_development