Lots of cities have had remote workers leave, permanently or temporarily, for obvious reasons. Is there anything showing that SF is somehow worse?
What I do believe I see is a strong relationship between reactionary/GOP political messaging and what is repeated about cities. The Republican National Convention's focus was the 'chaos' in cities, IIRC, though few noticed because other issues dominated. Reactionary messaging seems inredibly effective; whatever they say, people of all stripes are soon repeating. The emotionally intense, repetitive style also seems to match it - I don't see many reasoned arguments.
It can absolutely be self-fulfilling. Perception is reality. Look at many Americans worried about crime in cities, while crime is low and dropping. Homicides (a small portion) are up, but all over the place, not cities in particular. (Source: Recent FBI/DoJ report.) I live in a place with low crime, yet people say they are leaving because of it.
> A lot of the companies that ... went to Miami due to politics will never go back.
As of a few months ago, most people leaving SF went to the greater Bay Area, next elsewhere in CA, next the state of Washington.
Most companies go to SF for politics (or policy), but it's the norm and therefore unremakrable. You don't see a lot of leading companies outside the leading cities, maybe for a reason. Politics, especially when one group advocates ignorance, hate, and disrupting the rule of law, correlates with intelligent policy. Also, most people don't like living around ignorance, hate, and chaos.