why don't you learn your history organized crime is nothing more than a foot note in America terrorism is some that is and will be bigger than you love mobsters
and no mobs lack the know how to survive a nuclear Apocalypse they only care about profit and [censored] those they can get their dirty souls on
Actually, no one really knows the entirety of organized crime's impact on American history, at least indirectly. We're talking about Economics in general, rampant disease-like corruption, the war on drugs, the war on crime, failures on Wallstreet, Bobby Kennedy, Las Vegas, Chicago, prohibition, the Cuban revolution, and so on. And if you start to look at the influence on American culture and subcultures, you realize that all of that is just the tip of the iceberg. The main reason why it is a footnote is that the complexities of it are not fully documented, and that they are not quite as organized as movies and books might make you believe.
As far as whether they belong in a Fallout game, lets just say that reality has only rarely interfered with what does and does not make it into a video game. In any case, when the rule of government fails, greedy people start grabbing for more of everything (money, power, etc.) It's not hard to believe that, no matter how weak the mob is/was in the 50s, they could see WWIII as more than a mere inconvenience, and start taking advantage of it. Hey, survival of the fittest, right?