Counter argument: SF has one of the lowest vacancy rates in the country. https://sf.curbed.com/2019/3/21/18276227/vacancy-rate-san-jo... This article is promoting a bad faith argument used by anti development activists.
Sure it does. Houston has a higher vacancy rate, and much more affordable housing than San Francisco. This strongly suggests that the vacancy rate is a red herring.
A vacancy rate of 10% is an occupancy rate of 90%. To house everyone with a 90% occupancy rate, you need to have 100 / 90 in available housing stock, which is 111.1% of occupation requirements.
If you only build 110% of what is needed, and no one is homeless, the vacancy rate would be 9.1%, or ( 1 - 100/110 ) .
The point still stands. Cities need more housing than strictly required for residents.