Because the vast majority of Disney guests are NOT these board members. The people on this board make up a miniscule percentage of guests. For everyone here who complains prices are too high and they're done, there's 10 (I'm sure many more) other people going for the first time, or for a repeat trip.
But even on this board, how many people complain about the price, and then turn around and book their next trip?
As others have said, talk is cheap. If you're really fed up - stop going. Don't drop from a deluxe to a moderate, that does nothing. Just don't go, period. Otherwise you just continue being part of the problem.