In practice, it is probably impossible to innovate on housing materials in California- I doubt you could get a permit or insurance, which is a shame.

Plus, I and most people wouldn't personally want to buy a any type of stone or brick house- it would take a lot of evidence to convince me it was earthquake safe, and I'm not sure how one could produce such evidence. Resale value and demand would be very low for something unusual.

Wood houses in practice aren't a big problem. There is something like a 3% chance per century of a wood house burning down in California, and almost all of those are centered on specific locations that are known to be very high risk and can be avoided if desired.

In most cases you would escape safely and be covered by insurance (neither of which would be the case with a stone house in an earthquake). In California almost everyone has fire insurance, almost nobody can get earthquake insurance. Probably if a stone house was in a large fire, it would still be burned to bare walls and still be as unlivable and expensive to rebuild.