My guess would be just like anything in life, as long as someone is willing to pay then prices will continue to rise.
I can remember paying 5 cents for a loaf of bread, yesterday I paid $3.59. Gas used to be 25 cents a gallon, today I paid $4.29. My first house I paid $32,000 the one I live in now $170,000.
I think you get my point.
DH and I got our PAP in May and paid $499 each for them. We will attend approximately 25 days in 4 different trips this year. So that is $19.96 each day per person. Not bad in my eyes. Even at the $649 it would be $25.96 per person each day. Again not bad. We would be taking those 4 vacations even if we did not go to DLR.
I think $20-26 for a days entertainment is pretty darn cheap. We pay waaaay more than that to attend a local ball game.
Once again as long as people will pay the prices will reflect that fact.
Of cource this is just my observations.