There are so many cities (I'd say it's the majority in the world), with mixed use zoning which work wonderfully. Lower floors are offices or businesses and upper floors are apartments. Why is this so difficult?
In the case of the USA, though, another 'lens' on the legibility is that overall the people making the laws were neurotically concerned with keeping black people away from white people and enforcing segregation.
'separating uses' was a good way to also 'separate users', and a little barely-that-creative law-writing lets someone keep black people quite removed from the white people.
I found a document from 1922 that is upstream of all american zoning codes - it's what got ratified in Euclid v. Ambler circa 1926.
It's explicit goal was:
"To maintain harmonious relations between the races, care has been given to ensure adequate separation between the two, with room to grow without encroaching on the other"
The race-based zoning designations are gold:
"R1 - white, R2 - colored, R3 - undecided"
Here's a deep link straight to that portion of the document: https://josh.works/full-copy-of-1922-atlanta-zone-plan#race-...
Oh, it also says:
"The ordinary two or three story store and dwelling building is not a desirable type of construction from a public stand point. The regulations as applied will tend to reduce the number of flats that would otherwise be located over stores."
So - there it is. The goal of American zoning was, in part, to eliminate 'the ordinary two or three story store and dwelling building'.
Where I live, we have short term reuse laws that allow retail spaces to be used for residential, social, or other uses on a fixed basis. Typically a few years. The idea being to review the reassignment when the local needs change.
We get a lot of kindergartens that use these spaces, but also pharmacies, social clubs, and offices. Easy to move in and out.
Anyways, it's been a hot moment since I've paid attention, but years ago the guy that owned the hardware store on 44th Ave tried to convert into a mixed use building. I don't remember a lot of objection, but then the real estate market tanked and he went out of business. The apartments got built at least…