I'm not sure where this view might get more attention, but my feeling regarding price increases is that Walt (not to do a 'what would Walt do") wanted his park for the masses, to give the middle/lower classes a high quality place to play.
At a certain point, the person that will be able to afford to go to WDW.....will just as easily, actually go to Europe, or on a jungle safari. Why go to a pretend aquarium, when you can afford to go on a cruise. At a certain point, the middle/upper middle class who the parks were originally intended for, will simply find other venues (can you say Universal) and then, it might be late for WDW to get them back.