Even if you exclude zoning from the equation entirely and look at the raw material and labor costs associated with building it’s usually exceeding most definitions of “affordable”. Density is often lauded as a solution, but building vertically is more expensive than horizontally. It only helps spread land costs across more square footage. The costs of going vertical usually outpaces the savings of diluted land cost. So there’s really no solution that’s sustainable. The result being all affordable housing is a shell game of subsidies.

Some of this is our own doing as well as we continue to up the requirements of building standards/codes. Some make more sense than others, but in general we don’t design building codes with costs in mind and I feel that’s a pretty large recipe for disaster.