Specialist jobs aren't bound to countries like skilled jobs (I consider specialist jobs a subset of the skilled jobs); a specialist, say an academic, an artist, an archaeologist etc. is a skilled worker that is not in universal demand, and is thus more apt to move to a job. They're not like accountants, plumbers, electricians, high school teachers or salespeople. They aren't in demand everywhere, so they move to a place where they would be in demand. That's the beautiful fluidity of the workforce; job candidates go to the job, wherever it may be. It's one of the best things the US has going for it; if you can't find a job here, go somewhere else. It's a natural component of a free market.
Specialist jobs are usually preceded by a specialist education (which means travel will probably be involved). I'm a musicology student. Do you have any idea how few schools offer programs in musicology? And of those which are the best? Of course not! It's a specialized area of study. I'm lucky that I only travelled 700 miles for my undergrad. And I have no idea where I'll be teaching, let alone where I'll finish my education up through PhD (though I have very certain preferences...). You can't put the same limitations on specialist positions as you do on most skilled professions.