You are generalizing and exaggerating the problems that California has. Wild fires are not a problem in all of California including populated places like LA or SF. Earthquakes and wild fires have not devastated all of California. The whole South West will probably deal with water issues in the coming decades, so California is not unique to this. These seem like things you are thinking of due to recency bias. Air pollution is a problem in a lot of big cities. Expensive cost of living is a real concern, but that's not an issue for those who are willing to live a diminished "quality" of life or those who are extremely wealthy. California has the highest number of millenial millionaires moving it for a reason.
Most of California has great year round weather. There is a diverse natural landscape there, that many places in the United States or the world lacks. You can find deserts, cold mountainous regions, beaches, etc. All these natural factors are the reason why I find California beautiful and appealing. It's also the reason why people live there despite some serious problems, some of which you mentioned. When you live there for an extended period of time and become accustomed to that Cali weather, vibe, and general lifestyle, you will understand. Many people are OK with not living in California, and that's fine too. I think California is a place that once you become used to what it offers, it's a place that you don't want to leave, even if it is more logical to do so for practical reasons.
I'm not diminishing anything you said. You have mentioned some valid reasons for not living in California, but to paint it as undesirable is too extreme. There are plenty of reasons for California being desirable. They might not be reasons you care for or reasons that outweigh the negatives for you.
I hate to say this, but what I've noticed about people who left California, most of them left because of practical reasons and list those as reasons why they wouldn't move back. Often times, they are middle class folk who could not handle the hardships of living in a state with such a high COL. Raising kids and driving an hour in traffic to get to work is not fun, even if you live in a cool city.
People who had plenty of money or good living situations, never complained and never had a desire to leave, other than casually mentioning it's very expensive to live there. Then there are those who hate California for the obvious reasons, and when they finally move there, they convert to those typical California lovers.
A better way of putting this is that California is not a perfect paradise, and there are reasons for liking and disliking it.