its not that far in the future AFAIK, and as far as I can tell its a revival of old fashions. The buses look old but they're nuclear powered, and I imagine the cars are as well.
There was a giant war by the timeline of Fallout. This implies there was a huge nuclear war which caused a, you guessed it, nuclear fallout. The game is set in the time of the fallout. Because of the war, you can easily assume much technology was set back and little was salvagable. You have some futuristic stuff left over such as laser guns and stuff like that, but for the most part, the war took its toll on the technological age. It is so 50's-esque to show the regression societally and technologically.
I always assumed that the nuclear wars that happened in the Fallout universe happened during the "Post WWII Cold War" era of the real world time line. Which is why technology seems so dated in the game.
Fallout is awesome and that's that. Personally I like this post-apocalyptic old stuff. It's a pretty fresh and awesome idea.
Fallout isn´t based on our universe :O "The Fallout world exists in an alternate timeline that split away from the history of the real world following World War II. Up until the Great War in 2077, the Fallout world was dominated by the distinctively American culture of the 1950s, though with a far more advanced technological progression. The Fallout world's setting is heavily influenced by the science fiction anthology Worlds of Tomorrow, which was released during the Golden Age of Science Fiction in the 1950s. " (taken from fallout wiki)
