Of course, I am not talking about everything. But, some of the more spectacular ones should be almost automatically be shared by, at least, the US parks. It's not like there aren't many examples of that, and I hear very little in the line of "it shouldn't be here" discussion. Just looking at MK... Jungle Cruise, Pirates, Tiki Room, Splash Mountain, Big Thunder Mtn., the Side Wheeler, Haunted Mansion, Small World, Carousel, Speedway, Buzz Lightyear and others that I am sure I missed. It is obvious that it never was a Disney policy to not duplicate attractions.
You are correct many probably want to and will have the means available to hop across country just to ride a silly 2 minute ride, but, even those that have the resources available are not going to automatically do that, but, how about the thousands that don't have the financial ability or even the time... to go across country. No one has given me a logical explanation why that isn't done as much anymore. California Adventure, the original at least, I haven't seen the upgrade, was filled with Epcot type/DHS type of experiences. Epcot was unique and it apparently didn't have the staying power, so it is not likely that they would be transported 3000 miles. Soarin made it from Cali. though (must have caught an updraft).
The most logical reason is the more impressive the attraction is the more it cost to build and that is the single trigger for it not being cloned US parks. That shouldn't be agreed with, but, like so many other comments heard about Disney Management it should be condemned as nothing more then another money hording decision they made that excluded a whole lot of people from experiencing that particular part of the "magic".