The price range of a Disney vacation is huge.
We have done the trip where we stayed off-site, drove from Boston (we actually like that part), brought all our snacks into the park, ate out only once a day and never in Disney restaurants because they were too expensive. We had a blast.
Eight years later we are no longer paying $35K / year in daycare fees, and we are coming this year for 16 nights in a DVC villa and bringing one of my daughter's friends at our expense. We are flying and renting a car, because the vacation days that would normally be used for driving are eaten up by our 3-days longer than usual stay. We are eating in one TS and one CS every day, because I promised my DH that we could 'faux'
DDP; we're not getting it because what it covers doesn't suit our style of eating, but he wants to see what it would be like to pretend. I expect that we will have a blast.
My parents are totally not theme park people, but when discussing with my mom last year why we keep going back I said: "Everyone always has a good time." It's as simple as that.
We know from experience that we can make a Disney vacation similar in cost to other vacations we would take as a family. If we need to, we'll cut back to this point for as long as it's still true that "everyone always has a good time." If we have cut as far as we can and still can't afford it, then we won't be able to afford vacationing most other places either which is a totally different question and not relevant to the one posed by the OP. And if we don't need to cut back but it's no longer a place where everyone in my family routinely has a blast -- then it's not really worth any amount of money, but I don't see that happening any time soon.