As the connections to Italy become more and more diluted with each generation it will impact on them. These days people intermarry into different cultures and are very much 'americanised'. There will always be crime but I don't see the 5 mafia families of New York surviving as they are now, they'll have to change the rules for induction. Once that happens it's dead, nobody emigrates from Italy anymore.

For instance The Irish mobs have more or less disappeared over the past 20 years, what's left is a few third and fourth generation street gangs in Boston and Philly. This will happen to the mafia, the families will be taken over/incorporated into bigger gangs comprised of people from all different backgrounds, severing the link to the home country in the process.