To be fair, the Fallout universe had a local nuclear exchange in the middle east before things got really desperate. Eventually the only oil left was found in Alaska so China invaded, Canada is annexed in to the US and after months of bloody stalemate the Chinese are forced out of North America. Meanwhile, a silly lethal plague is making it's way around the world (by which I mean the western world) prompting fears of a Chinese attack. Hysteria is at a fever pitch and work is begun on what will eventually become the FEV (the green goo where Supermutants come from). The US invades China using the latest top of the line power armor and cut through Chinese defenses with surprising ease. Sometime thereafter, a world wide nuclear exchange is initiated (though nobody officially knows who did it, China was in Dire straits and are the most likely culprit, though there is some argument to be made that the US launched a botched first strike). For two hours fire rains from the sky and most life on earth is eradicated. Twenty years or so later, the first game opens.katsabas said:
If I had a point there it is simply that the war did not last centuries - just a few years and a desperate lack of resources was enough. Strangely enough, considering everything was nuclear powered according to Fallout 3 gas shortages were a major concern. I mean, you can just find fusion batteries in convience stores for crying out loud.
