spdrun, those large swaths of “vacant land” in the peninsula (and in ALL bay area counties) you’re seeing on your map-reading expeditions from your comfy perch in Manhattan, NYC are protected. By that I mean they are National or state preserves and/or parkland. As such, they will NEVER be built on so there goes your “gentrification theory.”
No need to be insulting. I know about the parkland, which is why I was speaking strictly to already-developed areas like EPA and parts of Oakland.