Most people who have any extra $$'s after necessary basics of housing, food, clothing, medical, etc. choose what they want to spend the extra on whether it be fancier clothing, cars, deluxe vacations, smoking, drinking, etc. etc. There are a lot of everyday things that some people consider necessities that are no where near that.
Yes, Disney is expensive, but you also get a lot for your admission $$'s there compared to other venues. Other than that (and fuel for our vehicle), most other costs can be cut to the bone. We did at one point when our children were small, so I know it can be done. We never spent beyond our means, but had a great time. Either camping, or staying offsite, bringing snacks/sandwiches in, then eating offsite makes a 'big' difference on the cost.
Is it what most of us would choose? No, not us, anyway, but we did it to be able to go, and no regrets, but have great memories. Now, we can do mostly what we want, but we still don't spend half of what I see people list on here as their vacations costing, and we are totally happy with that.
Some people stay broke no matter what their income - we have positive proof in a close family member/couple over many years - easy come, easy go. They still can't figure out how we have always had and done more (with no debt) than them with only one income (I was a SAHM).