Rich people don't have to leave a state to use tax avoidance strategies. I live in Washington state. The recent state tax increases have reduced total state tax revenue. That's the point of the Laffer curve, tax rate increases result in less tax revenue. Now exactly the shape of the curve, that's hard to say. But you are obviously past the maximum when a rate increase reduces tax revenue.

PS The last several CA (I used to live there) tax increases resulted in decreased tax revenue too.