Rephrasing that, it's not mainly the cost. It's the focus. And the focus is where you spend more money. From what I've seen and read, a game for ps3 and 360 must be stunning otherwise it will have much more difficulties being 'accepted'. If for the Wii one thinks first "How are we going to use the wiimote?", for the other two it's more "Look at that screens". These are shortcomings for games, being prejudged by one part of it, and not the whole.