Huge swathes of the population are excluded from SF that would love to live there, as you note, by the high rents. But the high rents come from locals explicit

Huge swathes of the population are excluded from SF that would love to live there, as you note, by the high rents. But the high rents come from locals explicitly deciding that they don't want more people, and blocking housing. And that leads to lots of scapegoating of particular classes of people based on group characteristics, in order to justify the exclusion. Whether it's people moving from the Midwest, or people in tech, or (when my wife lived in the inner subset) all those people at UCSF. There's a huge amount of "othering" in SF that people use to justify their need to keep people out. And I would say that it's far more prevalent and accepted than anti-immigrant bias in the Midwest, for example. There are way too many people in SF that try to be "cool" by distancing themselves from all those people that arrived in the city after them. The core problem is the idea that a city is for the people that were born there, rather than cities are for everyone.