@nathanpitman @liroyleshed So companies like Google pay by geography because what makes a comfortable living in Pittsburgh is near the edge of the poverty line in Mountain View.
They pay more in Cali because if they didn't, nobody would work for them. They pay less in Pittsburgh because people aren't leaving at that salary; there's nobody else to work for paying that well.
... if employees flowed fluidly from place to place, the salaries would equal out, but it turns out a lot of folk living in Pittsburgh don't want to live in Mountain View, not because it's expensive but because it's... Mountain View. And so on.