Spaghetti westerns were still stories that happened in the USA or USA/Mexico border and with USA actors and using (loosely) USA history. Because they couldn't be played anywhere else, because they are westerns... I'm not overstating though, it's in the subtle messages. How about the levels of Patriotist that would allow to show a soldier executing a prisoner on TV, laughing and then wave at the camera, with a Patriotic logo of "Our dedicated boys keep the peace in newly annexed Canada". Then showing a proud Power Armored Soldier with the USA flag flying in the wind. Definitely a parody of the logos used in World War 2 news videos in the USA. Or the, "black and white Disney-like cartoon style" of the Vault Boy in the intro? Even the poster advertisement for the Vaults is totally in a USA style, the Call Now! with the art style for the people in it, even their happy facial expressions while a nuclear bomb explodes in the distance is typical of the american advertisement in the 50's USA. Or the Corvega ad on the TV. And even the style of the car is totally USA muscle car culture. And all of this is just in the intro of the first game. Then there is the capitalistic nature of the companies in the setting. Tell me, where else in the world do companies act like in Fallout (although quite exaggerated in it)? Can you have a Fallout in Russia or China that has companies behave like they did in Fallout? Can you have a Fallout in Europe like that? I mentioned the cold-war feeling of the games too. Apart from Russia (I assume), most other countries didn't really had this daily dread over their lives, this specific culture and reality. Which uniquely influenced the USA culture, and we can feel some of that in the classic games. Even most of the black and white images in the "War Never Changes" intro are American. There's a reason why most or all of the great TC's for the classic games still happen in the USA, even when those TC's are made by Russians and other European teams. Because otherwise, it would lose part of it's identity. Why would it be a Fallout game instead of "A *Insert country name here* Post-Apocalyptic game."?.