Shouldn't this be actually the better case (Apple not replying to a DMCA notification?). IANAL, but it seems the safe harbor policy of the DMCA don't apply if the service provider just ignores DMCA notification. Which means you don't need to go after the person who actually put a copy of your software into the app store, but you can directly go after Apple. The facts in that case seem to be relatively clear, so the risk of losing in court against Apple should be low.
The only problem is that Apple could retaliate and block the developer from using the app store in the future. In the end, Apple's store is Apple's, and they decide when a developer is more a nuisance than a boon for Apple's businesses.