Well, for me personally, I think they are all out of whack when I compare them to just the cost of tips/wifi (which are high in and of themselves - mostly wifi), and I choose to either buy drinks individually, or just bring what I want to drink onboard with me at embarkation or ports (non alcoholic I mean, not sure if they will let you take alcohol onboard if they are paying attention to it). We cruise mostly with Princess, and their prices are cheaper than Celebrity, although not by a whole lot anymore, and I don't do it with them either.
It is however, an individual choice, no different than buying a car at the current marked up prices. People want them, and buy them and that is their choice.