Those companies are definitely on the bleeding edge of remote work culture, but there seem to be many others who would hire someone remote if it were the right fit (my company for example). I've been contacted by outside recruiters and corporate recruiters big and small, but when in comes to bay area they always seem to be hellbent on you being on site.
Then again, maybe it's because I'm not really looking, and I'm being contacted by those who are just grasping at straws at that point.
That's a good point -- not willing to relocate can certainly be interpreted ambiguously.
My company is a mid-stage startup of ~30 distributed across Cincinnati (75%), NYC (20%), and SF (5%). I would say we're semi-remote: most of our tech team works from home 1-4 days per week. I've personally done a few trips working remotely in another U.S. city one week at a time. In our case the culture isn't quite ready to accommodate a person being fully remote, though I'm hoping to be the guinea pig.
For anyone reading this and looking for fully remote, there's a nice "database" of remote jobs in this GitHub repo.
Then again, maybe it's because I'm not really looking, and I'm being contacted by those who are just grasping at straws at that point.