It doesn't have to be affordable to the working class, it just has to be affordable enough for a few engineers who saved up a bit in the last boom to take a ~5-

It doesn't have to be affordable to the working class, it just has to be affordable enough for a few engineers who saved up a bit in the last boom to take a ~5-year sabbatical. Then fear of falling into the struggling working class motivates them to keep inventing, while a desire to replace all the working-class employees who can no longer afford to live in the city gives them a ready-made market. There's no guarantee that the working class as we know it today (i.e. those who perform repetitive tasks with their hands) will continue to exist. Most of the Bay Area's history has been about automating and replacing progressively higher-level portions of the economy with machines.