So actually, Japan does something like this. Residences can be built pretty much anywhere (except near super heavy industry), because their zoning is all about how much of a nuisance something is. They also don’t have strict usage restrictions like Euclidean zoning in the states. So for example, if something is zoned for medium commercial (making that up), you can build everything from commercial “down” (so to residential), which allows mixed use too.

And let’s not be flippant. Nobody wants the ability to build anything anywhere, but it’s eaually absurd to not build much of anything at all. You can have density and affordable housing and a good quality of life; lots of cities do it already!