Heck, I used to work for Disney. I remember at one of the presentations with one of the higher-ups it was noted that the younger a person is when they make their first visit to a Disney park, the more likely they are to be the type of person who continues to visit the parks as an adult. It is straight-up indoctrination. They cited the specific statistic (i.e. "if a person visits a Disney park for the first time before age X, then they are Y% more likely to become an adult passholder) but I do not remember the exact numbers off the top of my head.