I disagree. Taxes haven't materially changed in California in a decade. People are leaving because they aren't happy here. Look around, you don't see a lot of smiling faces.
The $10,000-deduction limit on State and Local Taxes (SALT) materially changed the calculation for highly compensated tech workers. It effectively raised federal taxes for people living in high-tax states, of which California is way up there.
That's a good point, but that could change. Its being negotiated right now.
People could leave SF and stay somewhere on coast. California has beautiful and diverse countryside.
I wrote "uncertainty" because things may change very soon.
Trump and the Republicans raised my California state taxes a lot.