In one hundred years governments will realize the economic benefits of allowing full mobility of all citizens to both leave and arrive at will. (Not every single nation will agree, but 95% will.) Furthermore, this notion of universal free-movement will seem so obvious and natural that it will become hard to argue against. It will be taken as an unalienable right like free speech, or one person-one vote. Paradoxically this free-movement right will ease the volume of horrific mass migrations, since there will be constant daily mini-migrations that are also self-correcting.
Challenge Kevin Kelly to a bet on this prediction!