Super Happy Cow: That was in a period where there weren't very many multiplayer games. Now you have a huge selection of multiplayer-only games, so unless this would draw a huge, sustainable crowd, it's just a waste of money and detracts from the single-player experience.
Enemy Territory still exists and is still free. I think more than any other game, Quake 4 showed that there was no need to recreate the same multiplayer with diminishing returns on popularity, and I can only see this as being a smart decision on the developers part. Ofcourse, it's working for Call of Duty, but as a…