SF is probably hit the hardest by WFH. If you lived and worked in the city you probably had a pretty good commute, so you're not getting the biggest benefit. And while I know it's a less common preference on HN, a lot of people enjoy going in to a lively office and occasionally grabbing drinks with your coworkers after work. It's a great way to make new friends. But with WFH there's a prisoners dilemma where no-one goes in because no-one goes in. Hard to justify living in one of the most expensive cities in the world at that point.

As a side note, I've been reading a lot of comments like the one below describing SF as a "nightmarish hellscape" and I just want to caution people to not read into things too much. I've spent a lot of time in both SF and Seattle, and while there's specific streets you want to avoid, and you can (rarely) run into weird or disturbed people in other areas (like most major cities) overall they're lovely places if you can afford them.