It's not; there are literally tens of thousands of new units currently under construction[1] in the City. The issue people have is most proposals for new construction in San Francisco consist almost exclusively of luxury housing.
There's no shortage of housing in San Francisco, only a shortage of affordable housing.
There's no shortage of housing in San Francisco, only a shortage of affordable housing.
[1] http://paragon-re.com/San_Francisco_Housing_Development_Repo...