The NIMBY effect in SF is very real and there is lots of strong evidence from both academic and industry analysis. For example there are several indices of cons

The NIMBY effect in SF is very real and there is lots of strong evidence from both academic and industry analysis. For example there are several indices of construction regulation and SF is usually near the top: http://realestate.wharton.upenn.edu/research/papers.php?paper=558 http://realestate.wharton.upenn.edu/research/papers.php?pape... So despite this why is there a building "boom"? Basically prices (rents and sales) have gotten so very, very high that it again makes sense to build in SF. And as mentioned this "boom" is relatively modest. To give you some flavor: the new housing (and office) construction is almost exclusively at the high-end of the market. This is because NIMBY and other policies have made it cost around $750,000 to build a unit of housing in SF. So as long as prices and rents can justify this spending taking into account risk, time, required return, etc. developers will build.