My working hypothesis for why programmer-employees in the Bay Area and New York City get paid more is that so many of them have a credible alternative to being

My working hypothesis for why programmer-employees in the Bay Area and New York City get paid more is that so many of them have a credible alternative to being an employee, namely becoming a startup founder, which I imagine has helped them in salary negotiations. This map near the start of the OP makes me wonder whether, similar to the markets in the Bay Area and New York, the markets in Switzerland and Norway give programmers some credible alternative (not available in for example Ukraine or Vietnam) that can be resorted to by a large fraction of programmer-employees.