Absolutely, the transportation issue is big. If someone is within driving distance of Disney I can see where it becomes much more affordable. But there is still the cost of tickets if you have a larger family. For you (I see you have no kids

) it's a no-brainer, but for my family it's 1500 dollars just for tickets to the park

Add on accomodations (Disney doesn't provide affordable accomodations to families like mine) and even with a PIN at a value I'm at 1500 dollars easy. Now we have to eat..................ok imagine feeding 6 in the parks for a week

THIS is affordable
And you actually bring up another questionable argument when you say with your Disney vacation you know that everything is paid for. I'm assuming that when you say 'everything is paid for' what you mean is the price of the admission to the parks is the total cost of your entertainment. While that may be true for a couple of years I would imagine that at some point a family would like to branch out and do something more than the just the parks. I know I would. Sure I love all the rides and shows and parades but year after year after year? I'd have to mix it up a bit to keep it new and interesting. So what then? Golf? Horseback riding? Water parks? Spas? Back stage tours? The possibilities are endless. And so are the dollar signs!!!!!!! So sure, a generic Disney vacation (still wonderful yes; but generic nonetheless) may be an affordable/less expensive option...............................but once you start adding in a few bells and whistles, absolutely not.
So I'm going to have to add the size of ones family and how desirous a family is for variety as two of the other major factors to consider when determining whether Disney is an affordable/less expensive option (when we go to Canada we can stay in a beautiful fully equipped 2 bedroom/2 bath condo at the base of a gorgeous mountain in a European styled pedestrian village and enjoy shopping, swimming, boating, hiking, biking, zip lines, luge etc. etc. as well as family entertainment for over a week for LESS than 3 grand complete!!! Now that's what I call affordable

)