I go because I love amusement parks, and Disney are some of the best around. In the last year I’ve spent 66 days in a park (22 at DLR, 12 at Universal, 6 at Cedar Point and Busch Gardens Williamsburg, 4 at DLP, Dollywood and Silver Dollar City, 3 at Knotts, 2 at Kings Island, 1 at Holiday World, Mall of America and Canadas Wonderland.) I’ve done other trips too, to places from National Parks, Beaches, Cities, etc. I will say it again, entertainment wise, no other type of vacation offers a better value than a theme park. Only places where I am responsible for my own entertainment ie I have to take an active part in planning and then doing an activity (like a beach, museum or National Park) are cheaper.
Any trip’s biggest costs are going to be transportation and lodging and that can be as cheap or as expensive as you want it to be. No other activity where you essentially just need to show up can average down to less then $10 per hour anywhere. Heck with my AP/season pass skills I can get that number down to under $5 an hour in some parks/chains but I’m extreme/not normal.