Different states have different numbers of cases due to the different measures that have been taken. Bay Area quarantined early, and has been stricter than most of the country, followed by California at large. It's not like different states net different results simply due to magic.
So if you want to loosen up restrictions in California, it shouldn't be grounded in the fact that California seems to just be impervious. What you're proposing would be in direct contradiction with the reason why California has lower numbers. There's nothing necessarily wrong with that, as there is an ideological case to be made for measuring liberty against security, but the lower number of cases is totally irrelevant for substantiating that position.