the bay area has lots of scope for greenfield development. manhattanize mare island for chrissake. south of SF there’s lots of land, most of which should remain protected but we could develop a few pinprick microcities and add hundreds of thousands of homes.

i think you underestimate how hard, both politically and physically, scaling up in real bulk primarily by infill would be. this is my core disagreement with YIMBYism — identified the right problem! chose the right goals (lots more housing!) then limited itself to impractically disruptive means.