They do those things because they have to compete with everyone in general. If employees want parental leave and will choose the company that provides parental leave over the company that provides <savings from not providing parental leave> in additional salary, companies will offer parental leave regardless of what California requires. And likewise if employees preferred the additional salary over the parental leave, they would provide that in a place the law allows it, even if that isn't allowed in California. But tech employees frequently prefer the flexibility to the money (because the money is still pretty good regardless).

The exception to this is things like CARB where companies will design a car to meet California's fuel economy requirements, but then that model exists and can be purchased by anyone regardless of whether they live in California. If something has a fixed cost, the law in one place requires it, and that place is important enough to justify paying it to operate there, it gets companies to pay the cost. But that doesn't really apply to variable costs like employee benefits.

And I know my salary and benefits are abnormally good because the HQ is in the bay area. Local companies don't give as much.

I feel like I got the best draw by working for a CA company outside of CA.