This popular mythology in certain circles but it relies on people not calculating the effective total tax rate, including local and property taxes, and in that case California is the 13th cheapest state in the country:

https://wallethub.com/edu/best-worst-states-to-be-a-taxpayer...

You also want to consider what your taxes fund – for example, a startup founder probably benefits from proximity to two of the best university systems in the country and the better quality of life means you get more top people in your employee and networking pools. The ultra-rich are going to leave but a founder who isn’t already in the top income bracket is making an economically rational decision.