This market efficiency/rational agent argument often doesn't hold up. For you, it does, because you're probably highly intelligent, highly educated, and have so

This market efficiency/rational agent argument often doesn't hold up. For you, it does, because you're probably highly intelligent, highly educated, and have some baseline wealth. But at the margins, if someone has 80 IQ, perhaps has some mental health issues, doesn't know anyone anywhere outside of SF, and isn't even aware of the fact that SF is comparatively much more expensive because they've never travelled and aren't online like we are, and doesn't have the money that it takes to pick up and move, let alone the cognitive planning ability to take the required sequence of actions, they can easily fall through the cracks and become homeless.