Looking at a few non-SV cities such as Seattle, Chicago, Nashville, Orlando, Sacramento, Austin, and Fresno it costs $14-18k/year more to rent a 1 bedroom apartment in the Bay Area than to rent in those other places.
The average monthly spending on food in SF is about $150/month more than the US average. That's under $2K/year.
California does have a high income tax. For someone moving from somewhere else to California you might have to pay them maybe 10% more to compensate for that.
Putting it all together, a job that pays around $100k/year in non-SV non-NY decent sized cities should need to pay if we are generous maybe around $140k/year due to higher COL in the Bay Area.
That Bay Area tech pay is way more than that suggests that something other than SV COL is the main factor.
People are saying $350k remote jobs don't exist. Which obviously is untrue (go work at Airbnb). But they're exceedingly rare.