I make bread at home, it's not a complicated recipe. I'm pretty sure they could do it in California as well, but it's unlikely they will like it (something about being "too crusty" ?).
I'm fairly sure that they do do it in California, San Francisco Sourdough is a whole bread style, they have world-famous bakeries and the crust definitely isn't an issue https://tartinebakery.com/
Anyway, here's a working recipe if anyone wants to try it : https://www.lesfousdeterroirs.fr/nos-recettes/pain-maison