The thing is, why WOULDN'T they charge that much? I know people that only play FPS multiplayer, particularly Halo. A friend of mine literally has only played Halo multiplayer since Halo 3 came out. That is ALL that he plays. He has no problem dropping 40 for something like this because that is likely the only money he'll drop this year for games at all.
Regardless though, they make it that much because people will still buy it because people love Halo. Who are you to judge the price tag on that? They want to make a profit and I'm sure it will still sell (and if it doesn't, it will go down). It's funny Twigg, you seem to only get mad about the price of games that you either a) don't like; b) don't play; or c) play sometimes because of your addiction but could live without. Who cares? Just don't buy it.