I can see making certain times of the year more expensive. Make it where there are less people in the parks but they generate the same in ticket money, have less staff for that same time period and at the same time keep raising food prices. Make a potentially less crowded park with the same or more revenue.
A lot of businesses do this. Off hand, if a photographer charges low rates, they get more jobs but the editing and customer interaction eats up a lot of time. Raise your prices, you get less clients, make the same amount of money or more and work less overall.
As a consumer, you may not like it but you have the choice where to spend your dollars. I do not go to the movie theater anymore because they priced me out on tickets and concessions. I do not see the value and would rather watch it at home. if you find yourself priced out of Disney, look for something else, there are tons of other forms of entertainment you can attach yourself emotionally to.