I wonder what happened to George’s old policy of requiring everyone to move to San Diego?

That's comma.ai's policy since they make hardware and solve physical problems. The tiny corp has been hybrid (remote-first) since day 1 because it primarily writes open source software, and there's a long track record of success with remote for this kind of task.

We have a few whole-team meetups in Hong Kong each year for 2-4 weeks, and there's a San Diego or Hong Kong office that anyone can work from as they choose. We also have a wide array of fancy multi GPU boxes that everyone on the team gets full access to (known external contributors can get some access also).

I think many companies that were quick to embrace remote have walked it back, not everyone is capable of working productively remotely, nor are all types of work amenable to remote.