which insurers can operate in the state. Some of those conditions include restrictions on how much they can charge, which coverages they can provide, which coverages they must provide, the exposures they are allowed to exclude, etc.

When the state's requirements and limitations become so onerous that insurance companies cannot make money or no longer deem it worthwhile to do business in they state, they leave.

Insurance is the spreading of risk across a broad population so that insurance premiums paid by the entire insured population provide funds to cover losses by the (hopefully) few that suffer losses. If the losses regularly exceed the amount of premium taken in, insurers lose money. And if a state does not allow insurers to charge enough across their insured base to cover their losses and operating expenses, they lose money. That is what CA is doing — making it so difficult to do business that insurers no longer believe they can make money in the state.

None of these insurers is just deciding to leave because they want to stick it to CA. It is a huge market. But if they aren't making money in the state and don't expect to be able to any time soon, why should they stick around?