Walt Disney World has 4 theme parks, 2 water parks, over 30 resort hotels , most of which are individually themed and worth visiting on their own, a downtown area filled with great shopping and dining, championship golf courses, watercrafts you can rent, mini golf, a car racing experience...you get the idea. Don't try to see it all at once. It isn't humanly possible and besides, not seeing it all adds to the fun. As in: "Well, we didn't get to Blizzard Beach or DisneyQuest this time, but we'll catch those on our next trip." See how easy it is to get addicted?
Actually that's a great marketing game plan on Disney's part. By making it impossible for you to catch it all at once, they make it more attractive for you to come back. Clever, these folks! Sort of like putting nicotine in cigarettes, but Disney is actually very good for your health, unlike cigarettes.
When Walt Disney searched for a place for his East Coast theme park, he wanted to get enough land so the park won't be choked off by business and the surrounding city, the way Disneyland in Anaheim turned out to be. Consequently, the Disney Corporation, under the guise of various sham companies, bought a total of 47 sq miles (about twice the size of Manhattan) in Central FL, of which only about 1/3 is developed. When you're in WDW, you are immersed in the Disney environment, and it is very easy to forget there's a different world outside. Adding to the blessed isolation is the fact that WDW has their own very developed transportation system (boats, ferries, monorails, and buses), so you never have to drive while there. Unless you really want to.
Personally, I think the ability to NOT need a car is part of what makes a vacation restful. But I digress.
Below: A unique view of Monorail Purple (Picture credit: Me!)