While I agree that they probably are having a decent profit on accessories like controllers, electro-mechanical parts are surprisingly expensive in my experience. A good potentiometer or joystick can cost way more than the rest of the circuit that uses them.

> COD4 is apparently set in 2011 - do players not have automatic weapons anyway?

Sure, but with games being games, to make single-shot weapons interesting game designers usually make single-shot weapons more accurate and do more damage as a trade-off for their lack of automated fire. Of course with a rapid-fire controller you can get best of both worlds in that regard.