I live in SF. I had a car for about 5 years in the 90s, then got rid of it because it was such a hassle, and I was not one of those people taking off for the ski slopes every weekend.
Here are the costs involved, you can do the math:
Uber: Average of $10/ride to most places in the city if you ride by yourself. If you pool, it would be a third to half of that. Keep in mind, it is a small city with most people never venturing outside of a 3mile by 3 mile square Rail: Caltrain/Bart commute out of town will cost you an average of $8 each way.
Parking: About $350/month unless you live in a few neighborhoods where parking is easy
Tickets/Tow: About $400-$1000/ year - Parking enforcement is strict and unfair - (eg illegal tow signs put up with 12 hour notice and then cops signing off that they were there for 72 hours) Even pros getting parking tickets here occasionally. One tow is $1000, accidentally parking too close to a street corner with a ramp (considered handicap) is $900.
Liability insurance (you still need this if you are going to rent cars) - $300/year minimum
Breakins - Windows smashes are getting very common. So a replacement window periodically should be added.
Distance: Even if you have a car you probably won’t drive to work if you work in SF due to additional parking costs. You’ll take an uber or bus. If you work outside of SF you are probably looking at an average of 50 miles a day.