This is a question that interests me. I'm actually not sure that SF has more resistance to building than other cities once you consider that "SF" vs the general bay area is an artifact of an unusual way of managing municipal borders.
Keep in mind, what I'm saying here is a thesis, not a conclusion.
SF is city that ranges from very high density to middle density, with a few expensive and relatively suburban neighborhoods west of twin peaks and/or near the coast (St Francis Wood, Forest Hill, Seacliff, etc)… It has also had a relatively stable population density for over 50 years, and in some of these neighborhoods considerably longer than that.
SF is also a relatively small geographical area that is a different municipality from the nearby cities. In many (most?) cities in the US, sections of SF and Oakland/Berkeley would be the urban core of a larger city, but those suburbs and even exurbs wouldn't be considered different cities in the same region, they would be part of the same municipality. As a result, construction in the hinterlands that doesn't count as growth within "San Francisco" does count in growth in a place like Seattle, where the "city" of Seattle encompasses a much larger geographical area.
So, hear me out - while SF can be excessively preservation minded, think about how people would react if you tried to bulldoze not just the French Quarter in New Orleans, but the garden district, Bayou St John, or even some of the shotgun houses in less famous districts. What would happen if you tried to tear down historic houses in Philadelphia or Boston, or replace entire city blocks of 100+ year old houses or apartments with modern high rises?
My thesis (again, not a conclusion, I'd need to see the data) is that if you identify regions similar to SF - medium density neighborhoods that have existed in this form for 60-100 years, it is very difficult to tear things down and build greater density in many places outside SF. I wouldn't be surprised if it's especially difficult in SF, but I suspect this would be a difference in degree, that SF would have an unusually strong preservation instinct, but that you'd find strong, similar preservation instincts in many other comparable regions - but that these similarities are not evident because we aren't comparing similar geographical regions, again because of the oddity of municipal boundaries in SF (which are a large contributor to the NIMBYism problem, to be sure).