A 2-income family with 1-2 experienced devs working at major Bay Area companies could easily make over a million. But that only means they are rich as hell, it doesn't mean they are middle class. Median income in Santa Clara county is $140k so $150k was already a bit high as a starting point for middle class experience.

I won't argue that California isn't squeezing out lower incomes. That much is clear. But you're overestimating what that income is. Lower income families leave California because of housing costs, not because of income taxes. The median California household owes < $1000/yr in state income taxes.