Simple reason here...Everest is a coaster without any sort of 'coaster noise' coming from it. Namely, roars of the train, screams of the guests, etc. When you're up close to Everest, you can hear it, but outside of that, not really. In a park like Animal Kingdom with a lot of animals, the coasters need to be either quiet, or very far away from them so as not to disturb them, or ruin the theme for the guests. Building an outdoor spaghetti bowl like Dueling Dragons certainly would have done that.
-- PMM
