Well for me, I've lived close to Disney for pretty much my entire life, so it has just about BECOME my life. I go on Disney cruises and vacations, buy Disney shirts, hum Disney songs while doing laundry... I couldn't imagine NOT going back to Disney lol.
And to agree with MonorailDriver, it is an escape. One time while en route to Animal Kingdom, my car was sideswiped, then my E-Pass (for tolls) didn't register, and my simple endeavour to buy a loaf of French bread for dinner later that evening failed when I couldn't find it at three different stores. But I drove into the gates of Disney, and ahhh... it melts away. The world doesn't exist when you are at Disney.
On the note of $$$, there is PLENTY to do at Disney for free or close to free- Downtown Disney, resort hopping, mini-golf, etc. I have an annual pass, but I've spent many days not even going to the parks, just having a nice day out to see a movie at DTD and then playing a round of mini golf and snapping some pictures. I used to babysit my sisters-in-law when they were small, and I'd bring them to DTD to keep them occupied. For just the cost of gas and a few cheeseburgers at the Micky D's there, they were kept happy and busy for hours. I think that's a pretty good deal!
With the money crunch lately, we've scaled back our deluxe visits and have tried the value resorts, which we enjoyed. We always bring our own drinks and snacks (even when we were splurging at the deluxes, having a 12-pack of soda is always a good idea!), and it cuts back on our spending so much that we are able to take many more trips than if we'd eaten out. I know that eating out is part of "the experience," but we've been there so many times that now we'd rather be cheapskates and be able to stay more often. And there are good food deals as well. I am particularly fond of the food courts in Port Orleans Riverside and All-Star Movies, consisting of "build-your-own" type of meals. My husband and I get away with an $18 dinner, and we are completely stuffed. We also enjoy Trail's End Buffet at Fort Wilderness. They have the best breakfast buffet- MMMM Mickey waffles!!!

There are plenty of ways to save money and have fun, you just have to find them.