You're forgetting about those who have spent at least 1 day in commitment of a mental health facility also lose their federal firearm rights via 922(g)(4) (Generally CA WIC 5250).
California is one of 16 states (+ Washington DC, and all the US territories except for Guam) that doesn't have a federal rights restoration process compliant under 34 USC § 40915. In the 9th circuit standing precedent is
Duy Mai v. United States which essentially held that it was fine that Duy Mai restored his state firearm rights via state court (Washington), but that it did not restore his federal rights, and that 925(c) was defunded (at the time), and it was essentially the intention of congress that he have no path to restoring his federal firearm rights. He was denied En Banc. Such an unjust ruling... though that was pre-Bruen; I doubt a similar case would have the same result. (
Edit: Anyone reading, read the conclusion on
Duy Mai v. United States. It was just such a terrible opinion)
Anyhow, so basically the now reformulated 925(c) rights restoration process opens up a pathway to those who have had a 5250 stay in California to restore their federal rights. Those who have had an involuntary stay via 5250 get their state firearm rights automatically restored after 5 years unless petitioned early, so the sticking point has always been on the federal/925(g)(4) end.
Lot of Californians are going to have the opportunity to get their firearm rights back. Numbers wise... Looks like there were roughly ~30,000 5250 involuntary commitments in 2021 (
Appendix A, PDF page 12)? That's a lot of people annually if those numbers are mostly consistent year to year.