Background: Grad student studying local and state government, in particular California.
Yes the state has higher than average income tax rates. We also have some of the lowest property tax rates in country that get locked into only very small increases each year. Furthermore, the investments in education and technology have helped the state to strive and grow. Areas such as Austin and Denver and North Carolina have growing tech start-up vibes but there's still a reason most everyone heads to California to get started.
Additionally, this is just a ploy by a small group of rural counties to get some attention. They largely benefit far more by being a part of California than they would without it.