Right now, California does not allow pricing of insurance policies except on a few non-standard factors. These factors do not include "proximity to wildfire risk areas", which means that insurers lost a lot of money in the big wildfires of 2017-2018. The state refuses to change, so the insurers are pulling out of the market.
Framing this as "because of wildfires" is technically true, but misses the point. The problem is that insurers in CA can't accurately price for wildfire risk.