Canada already has some stiff immigration requirements, and no country wants a wave of pedo-friendly degenerate amoral Democrat 'refugees' swarming into their neighborhoods, so I certainly wouldn't blame them if they did build one
Wall Street will make some fancy new fan-dangled financial instruments involving Mexico, so that investors can buy shares in Wall building stocks of both walls. . . .
I'm sure they will find a way to make it profitable. . . somehow.