It seems in many parks I visit, I encounter people from those countries. Guadalupe mountains in Texas? apparently really popular abroad. Middle of nowhere, Oklahoma? Ran into a bus tour with French people.
Yet I'm from Latin America and despite being 'closer,' most people could not name more than 3 national parks (Grand canyon, yellowstone or yosemite). You go to US = you go to the stores (big emphasis on Outlets, Ross, TJmaxx and Burlington), you go to buy cheap electronics and clothes, you go to visit Disney or Vegas. "Ah yeah I have a cousin in Chicago, might go there to visit."
So where do people from Europe or Australia get that impetu to say "hmmm… Northern Thailand? boring. Nepal? boring. Patagonia? boring. Hey! let me book this year's vacation to Nothing, OK and visit this National Park not even Americans have heard about!"