Because world travel is not the easiest thing to do, first of all. It's very expensive, there are political issues, plus it's a lot more convenient to drive several hours on a tank of gas than to deal with flights, passports, luggage pickup, language barriers, etc. Furthermore, when traveling to a foreign land, most people would rather visit the country's historical landmarks and sites than to visit a Disney theme park. (i.e. Paris). There are millions of things to do in foreign lands that are way higher up on the totem pole than visiting a Disney park. If you travel all of the time, this may not seem to be a big deal, but for the novice traveler, this will be likely the only time they visit that area. Are they really going to spend their time at a Disney theme park instead of Versailles, the Louvre, or the Eiffel Tower, for example? Disney is at the bottom of the totem pole where the rhino is waiting, so to speak.