That lifestyle as a teacher is probably only desirable or realistic for the young. Once you want to settle down/have kids/whatever, you probably want to either buy a house, or not compromise quite so much. Does that mean that SF will have only young teachers? Most the experienced ones will move somewhere more affordable. Is that a problem for the city?

Or, all the teachers marry high-income partners and can thereby afford to continue living there.

~~I'm trying to find an article I'm sure I've seen on HN of marriages mapped by occupation. I'll edit if I can find it, but I believe I remember that teachers tended to "marry up".~~

EDIT: et-al found the link I was looking for. However, it doesn't seem to support my memory of teachers "marrying up".

Was it this interactive chart by Bloomberg?

https://www.bloomberg.com/graphics/2016-who-marries-whom/

YES! Thank you. I found another article on Bloomberg, but it was not this one. However, it doesn't seem to be support my memory of "marrying up".

wow thats an amazing chart to extrapolate from!

Young people come here for a temporary period and then leave. Only the ones become affluent enough stay.

Why would any teacher do that when they could live comfortably on that salary pretty much anywhere else in the country?

Well, teacher salaries are lower in other parts of the country (though it is also true that salary vs cost of living is less out of whack in most of them).