I've heard the idea to zone for one level above the average in an area, to avoid the wild west situation. Doubtful that would fly with some very rich single family neighbourhoods near cities, but perhaps it's too late for the gradual re-zoning and a more blunt approach is necessary.

Aside... where the heck is tech in building housing faster? Where's the prefab and automated assembly? Too many building regulations? Entrenched interests? Incredibly hard problem for large scale engineering?