This sort of thing is the problem I have have with software developers. It's not as profitable as they would have liked so they are 'pulling it'. If a business wants to enter the software as a service model they need to be prepared to support it indefinitely, unlock all the DLC at no cost, or release the code. With the App store being so locked down the second option is likely the most feasible, but under no scenario should they be able to pull it.
And before people start claiming that customers don't own the software - that's the very problem we need to solve.