You're looking at it from the wrong perpsective.
All of WDw is something that can be done without kids.
Attractions - Space Mountain, Philharmagic, Spaceship Earth, Test Track, Muppetvision, Tower of Terror, Expedition Everest, Tough to be a Bug, to name but a few.
Restaurants - Crystal Palace, Liberty Tree Tavern, Chef Mickey's, 'Ohana, Narcoosees, California Grill, Victoria and Alberts, Le Cellier, Rose and Crown, Garden Grill, Mama Melrose, Hollywood and Vine, Donald's Breakfastosaurus, Boma, and about a hundred more.
Shows, parades, fireworks, Pleasure Island clubs, Jellyrolls, 99 holes of golf, a dozen or more behind the scenes tours, 2 water parks, resort pools, spa treatments at GF, Illuminations and Wishes cruises, the Richard Petty Driving Experience...
The list goes on and on. EVERYTHING at WDW is for adults, if they have kids inside them.