"That suggests that high expenses are to blame for the departures, though not high taxes, as some claim, he said. California taxes wealthier people at much higher levels than those with lower incomes, he said.

“If those taxes were the motivation, you’d expect wealthy people to be moving out,” McGhee said, noting exceptions such as Elon Musk, a newly minted Texan. “By and large that’s not the people leaving the state.”"

https://www.nytimes.com/2021/09/02/us/where-californians-are-moving.html