Don't worry, once US is done with the middle east they will turn their geopolitical eye towards another war. Well have games based in china and north korea in no time.*raises hand*
There's only so many campaigns they can do before they begin to rehash similar environments and mission goals.
In 30 years there will be games where you play as a freedom-loving corporate security officer who must save america by liquidating hippy american dissidents (aka evil terrorists) who are attempting to bring down (terrorize) your selfless philanthropic trillion dollar multinational corporate conglomerate employer.