Here is my take on it. First a disclaimer, I like to read about Sicily, Italy and America BUT I find it much more enjoyable to read about things that happened in the United States, especially New York/New Jersey because that is where I'm from. I can only speak for myself but it's more fun reading a book and reading about what happened on 63rd street and you have been to that street, or that house or that restaurant. I'm guessing it would be the same for people who live in Sicily to read about the Sicilian Mafia, I think people are drawn to things they have experienced or visited before.