The longer we let SF be run by the ultra rich the worst it will get. Maybe when all the rich leave it will finally it rock bottom and the people will be able to pass the reforms needed to get the city back on the right track.
You can't bar anyone from cities. You can't bar them just like they can't bar you. It isn't policy that's driving anyone out. It's pricing, which is above the control of any one person or even group of people.
Some people will be forced out due to pricing. The local economy of every city is going to be unworkable at some income floor. The more expensive the city, the higher the floor.
If that floor is higher than what you make, it doesn't mean that no poor people live in SF. It just means that they feel poor even at a relatively higher income.
To illustrate, 80k per year is still a decent income in some towns. But it is definitely poor in NYC.