I think there is game theory at play. I don't think Google for example is leaving money on the table. They hire worldwide of course but they are not swapping US for cheaper countries on mass and it must be for a good reason. Maybe it's a missed opportunity and some YC company dominates the new arbitrage. Who knows! I think I like the soil analogy. Moving the palm tree to another spot is risky if it's doing well in its current soil.