Bay Area salaries are partly about location to begin with. This seems obvious, so I'm surprised by arguments that assume the contrary, usually in the form of "my salary reflects my value to the company, which doesn't go down when I move". The antecedent is a false assumption (the salary doesn't just reflect the employee's value to the company) so the argument is invalid.
Have you ever heard of a pay scale? Why on earth would you pay a senior engineer more than a junior engineer unless you believed their value to the company was greater?
