Eventually all the families will give way to general attrition - the last being the 5 NY families. I'm not sure how long it will take but they will always be Italian-American crime families for as long as they're around.
I do think the New York families will always be around in one form or another, but they will probably eventually mutate into something else. In 100 years they will be virtually unrecognizable I bet.
Things are going to get really interesting when the cohort of mobsters born between 1920-1940 finally dies out. As I have said before, when that happens, the Genovese family will probably turn into just another mob gang instead of the whole "Ivy League" thing.
For some reason I find the whole attrition process fascinating to observe.
