Crime and housing cost are not new. Most people fleeing California do that over tax uncertainty and general business unfriendliness. Stuff like retroactive income tax increase or exit tax.
But the overall trend is very disturbing. Crime may be old news, but the rate is higher than it has been in a while, and going up.
Housing is down recently from all-time highs, but still very high in absolute terms.
So none of this is new, but the Covid shock to the system has created the opportunity for people to leave in the way that there wasn't before.
San Francisco will be OK, wave after wave of rise and decline has been its way since the gold rush.
[1] https://www.sfchronicle.com/local/article/San-Francisco-s-cr...
I wrote "uncertainty" because things may change very soon.