While I think the mafia will eventually become even weaker then it is now, I don't think it will ever fully disappear. I can see the 5 families being whittled down to 2-3. The Genovese+Luccheses and the Gambinos+Bonanno+Colombos.

They could also relax the rules for made members. It may even be like that now where only an Italian father is needed (I know there have already been members with non Italian mothers being made like Jr Gotti).

There are always going to be Italian men who want to join that life.