> Silicon Valley FAANG engineers are paying almost 10% more in income tax than those in states like Washington or Texas without an income tax. So why did Silicon Valley grow up here rather than in those other states? At least in part it was the enormous public investment by the Department of Defense during the Cold War.

Prior to the 2018 Trump tax changes, state income tax was deductable on federal taxes, with the only limit being AMT, so the effective tax rate was significantly smaller than federal bracket + state bracket. Now, the limit of deductability is so low, it's almost meaningless. I don't know that silicon valley is tax averse enough to move away though.