> Also when we talk about long waits for Green Cards, we really mean for the large body of Indian technology workers, broadly speaking. For other nationalities the wait is typically a year or less (for those unaware there are effectively country based quotas for green cards). The gap in earning potential is even larger still in the Indian example vs my earlier UK one, so again I’m not surprised few actually move back.

From what I know, American based tech companies pay good salaries in countries like India as well. These are of course adjusted to cost of living, which is significantly lower. I don't think it's realistic to be working in a tech company in India and expecting silicon valley salary but the salaries people usually get is generally good enough for that region.