Games are about entertainment (essentially), not money. But the fact that some games are unique, better in gameplay, story, etc (and thus, produce more revenue) is what differentiates a game like World of Warcraft from say... Archlord. Or Diablo from Titan Quest. Money is just a bonus (a really big one at that, depending). If your game is liked, its a good game. If you're game is not liked it is not a good game. It doesn't matter if characters are imbalanced, or campaigns are too hard (or too easy); If the game sells, and people like it.. its a 'good game' by the player's standards. This may not pose true in a game designer's perspective, but it certainly hits the bong.
"Be aware of wonder"