User blog comment:Matthew Paul/Future Single-Player DLC Depends on Success of Leviathan/@comment-1978336-20120902203612/@comment-1958269-20120903174615

I don't know if it's true, but it sounds logical that MP packs are dependent on how many people are still playing. The more people who are playing, the greater the amount of player who purchase the packs is. Since the Single Player content has it's own price, they'll continue to make those as long as they sell, just as Patrick Weekes said.