ummm mission mouse, I believe they are already doing that - have you not eaten at a buffet recently?
Seriously ITA with you, Disney gets away with it because... they're Disney -
We ate at Crystal Palace one night, then a few nights later went to Cape May Buffet - same dessert offerings - and I'll look at pictures of Hollywood and VIne, and say that's the same dessert - now I'm sure many will come to the defense of Disney, as well they should, but Disney doesnt need our defense, they need our dollars...
(also I do realize that many buffets do have 'celebrated' items, like the zebra domes at Boma, but I did notice they also have the same dessert offering of a key lime tart, or another bite size treat! and it is a treat!) (I also remember reading that the Polynesian's Kona used to have a very special dessert - it was taken off the menu, but many here would request them, and the chef would make them upon request... not sure if I remember what that dessert item was... but it was there!!)