The whole structure of Call of Duty is as expensive as it is disposable. Each game carries lots of multilayer DLC (at premium prices); DLC that's required if you want the full online experience. It's disposable because in about a year, a new COD game will release, and most of the online player-base will migrate. With that new game, will be more multilayer DLC, and the previous game will plummet in value (current Amazon prices have vanilla MW3 at around $20, and Black Ops 2 at around $30) because not a lot of people will be playing it like before. There's simply no reason to keep the game around after the next game comes out. The online rapidly shrinks like a balloon losing air, and the singleplayer experience is a formality at best
So, People, vote with your wallets.