The thing is no one is coming after Tony at that point right? Everything has been sorted with NY and Leotardo is dead. I think in a way it was quite a clever ending, we were all expecting some hollywood ending, with a shoot out etc. Life goes on. Tony will probably get life and someone else will step up to run things. It was like the Wire, they didn't tie it all up and say it was over, Marlo was done, but someone else would step up to run the drug trade.