As we all know, the Kingpin is now in jail and, as revealed in the second season of Daredevil, he doesn't intend to go out until the streets of New York have been cleansed. Quite smart on his part - when the Punisher, Jessica Jones, Daredevil, Iron Fist, and Luke Cage have defeated all the serious threats, he will be there to become the ruler of New York, without anybody questioning his reign.
So when will that happen?
The Punisher will be released after the first season of The Defenders. So it isn't too difficult to assume that, by the time the spin-off arrives, New York will be cleansed. After all, what will the Defenders do, other than deal with the most powerful criminal organizations?
So even if Ben Barnes will be Bobby Saint, he'd still be some low-level mobster, among many others. And he'll answer to the Kingpin, one of the best and most charismatic villains of the MCU.