stigweard - the reason is simple - marketing. Americans are more likely to pay to see films set in the USA and told about Americans. Even the best "foreign" films that get wide release don't make the money you'd think they would.

I don't think the formula of buying the remake rights to successful foreign films and then retooling them for an American audience is really all that successful overall but in certain genres it has a history of being highly profitable. The best example of that is horror/supernatural and thrillers. Action follows 3rd. And, if a studio is lucky, they can get a franchise out of a translated horror film such as Ring/Ring II etc. For what it's worth, the novels that those original films are based on have finally all been translated into English and they are some of the best Science Fiction/horror I have ever read. You can get them on all Amazon now. The three titles are RING, SPIRAL and LOOP. Only the first one is like the film. the other two go off in quite unexpected directions.