[Epistemic status: very unsure. I sympathize with many YIMBY ideas and might support them on net; this post is me exaggerating the NIMBY parts of my brain to a degree I’m not sure I honestly support. This focuses on San Francisco to make it easier, but other cities exist too. Thanks to Nintil for some of the bright-line argument in part four. Conflict of interest notice: I live in a lower-density part of Oakland]