In my opinion, the only family outside of the northeast that could still be considered viable is Chicago. Once again, I use the term "viable" to mean that it meets the two basic RICO criteria - an ongoing pattern of crimes in behalf of an organization.

At this point, it's hard to argue Detroit really meets that criteria anymore. And certainly not any of the other families outside the northeast. And some past northeast families don't either, i.e. Buffalo/Rochester, NE Pennsylvania, and Pittsburgh.

So I suppose it depends on what you mean by "ceases to exist." As a viable family, most of them have already ceased to exist. But that doesn't mean every last member is dead or even inactive.