Nearly 75% of land in San Francisco alone is zoned for low density single-family or duplex homes. 37% of it is just for single-family homes alone. [1]
Nearly 98%(!!) of land in San Jose is zoned for single-family homes. [2]
Replacing every ~10 single family homes with even a 6-7 story apartment building can easily increase the supply necessary to reach equilibrium, and that's ignoring the fact that you can build affordable apartments that are >20 stories (see: Long Island City, New York).
Nearly 75% of land in San Francisco alone is zoned for low density single-family or duplex homes. 37% of it is just for single-family homes alone. [1]
Nearly 98%(!!) of land in San Jose is zoned for single-family homes. [2]
Replacing every ~10 single family homes with even a 6-7 story apartment building can easily increase the supply necessary to reach equilibrium, and that's ignoring the fact that you can build affordable apartments that are >20 stories (see: Long Island City, New York).
[1] https://www.latimes.com/politics/la-pol-ca-single-family-zon...
[2] https://haasinstitute.berkeley.edu/single-family-zoning-san-...