Cheaper land, safer location and the weather allows year round operation is why Disney chose Orlando Florida. Actually most of the land was purchased in Kissimmee as stealthily as possible which is a testimonial to his business savvy. A far cry from what runs it today.
Think of how you can visit Walt Disney World for Christmas and New Years or even Valentines Day. Now think of doing that in Maine, Minnesota or North Dakota. In a nutshell those are extremes but make the point fairly clear. Not to mention the cheap land was purchased for the Disney parks well before this area really took off by using dummy corporations. Unfortunately Walt Disney died before Disney World ever opened. Walt Disney's death was years ago in 1966. What year did Walt Disney World open? Walt Disney World opened on October 1st of 1971.
Walt Disney knew he was onto something big. especially after the wave of support and his successful purchase of all of that "Florida swampland" that nobody else wanted. Disney wanted the largest theme park in the world and he certainly got it. Now with Orlando International Airport and the two major highways Interstate-4 and the Florida Turnpike Disney World is legendary.