Who would you chose as an enemy then? In order for us to relate to the film/game/story we have to get involved somehow, care about it, clearly understand the two sides in the conflict and what seperates them.
It seems the best way to do that is to pick an enemy already engrained in the subconcious of the target audience. FPS or straight up action movies are easier, you set it anywhere with a heavy drugs trade and you have cartels and rebels. Set the film in the middle east and it's easy with the current climate to make bad guys for the protagonist to gun down.
For spy thrillers though, what enemies in recent times, have the funds, the manpower or the potential ability to really be able to fuck up the US (the target audience for most movies). I'd say you have Russia or China, so understandably pretty much all potential invasion/full scale attack stories have these guys as the antagonists. It may have been 20 years, but the cold war is etched in our minds still, especially with recent events such as the Russian spys recently discovered in the US and vice versa.
Try and substitute Russia for another country, lets say Belgium. Audiences wouldn't care because I'm guessing a fair few wouldn't even know where Belgium is, there has been no history between the US and Belgium, so to explain why Belgium suddenly plans to kill the president or steal valuable information would not make sense.
I know I've rambled on but I'll try and summarize. To be an effective villain in a story, there needs to be a level of threat that the population can feed off and get involved in. Americans would generally dismiss smaller countries as a non threat, or it would be too confusing to explain the motives and get to the action. When we stick to clearly defined "good and bad" we can get to the action quicker without needing much explanation so the majority of movie goers/fps players are kept happy.
