This is easier said than done. Making the density 2-3x is still a huge undertaking. With suburbs with single-family homes, this means bulldozing half of it an

This is easier said than done. Making the density 2-3x is still a huge undertaking. With suburbs with single-family homes, this means bulldozing half of it and somehow redrawing all the property lines so the lots are 1/2 - 1/3 as large and building new houses within the new lots. You can't just magically take a subdivision full of McMansions and somehow increase density 2-3x, unless all those houses take in boarders. Also, SF is still pretty unique compared to most American cities. So you might be able to do this stuff in SF, but not so much in places like Houston.