It is entirely a result of unregulated capitalism in the tech sector. Not policy. San Fran policy needs to stop coddling the trillion dollar babies. SF in the 70's and 80's was fine before techbros came along.
Another issue is high taxes in California (another left-wing idea). With taxes so high, the very rich are still rich and the middle class are living paycheck-to-paycheck essentially creating two classes: rich and poor. This is what happens in nearly every country that does this.