There is nuance here the OP did not address.
S&W did not cut off California. They continue to make fine handguns, and of course make occasional midstream production changes. Additionally, this microstamping stuff only applies to revolvers.
Calif. DOJ regards these midstream production changes [outside of sights and grips] - however trivial - as being a new gun model, which in turn requires new rounds of testing, fees, etc - and, for pistols - microstamping.
Even a change in location of parts manufacture - even if parts are of identical material & dimensions - is regarded as triggering of "new part" and thus triggers, in turn "new gun" - requiring re-Rostering.
S&W simply can't 'freeze' its production in old history. Tooling and material improvements and simple changes of machinery happen all the time in today's manufacturing environment - and today's "continuous improvement" mantra, the hallmark of most manufacturing operations worldwide - is precisely _stopped_ by CA DOJ.
While this offensive newer tack by DOJ also applies to revolvers, at least revolvers can be retested/reRostered in California without microstamping, a technology only the CA DOJ says exists reliably and yet which real-world manufaucturers can't implement (regardless of cost).
S&W has, luckily, gotten all streamed-in production changes to the M&P Shield guns and got them - along with the Sigma-derived SDVE 9/40 guns - Rostered before microstamping regulatory requirement was recently triggered. These guns _WILL_ be sold for the foreseeable future in California and re-Rostered. Revolvers that are Rostered (or re-Rostered or newly Rostered) will continue to be sold in California, and since microstamping is not required on revolvers, things are less severe in that field.
[Ruger's situation is similar but they may not have any designs that have been frozen without production changes, and thus all their autoloaders may disappear due to new microstamping requirement. Their DA revolver situation will likely track S&W's revolver status in CA - and their single-action Blackhawk/Vaquero line is exempt from Rostering in CA.]
I will note The Calguns Foundation is litigating (in a joint effort with SAF) the complete Roster regime in Federal court (major constitutional failboat). Alan Gura, of Heller and McDonald fame, is lead counsel.
Anyway, to review, details matter... S&W and Ruger are not 'pulling out' - they tried to do biz and tightened regulatory enforcement strictures do not allow them to participate nearly as fully in the CA market. For S&W, some autoloader product (Shield/SDVE) will continue to be present, and revolvers will continue to be sold and developed for CA.
Bill Wiese
The Calguns Foundation