I'll give you an example of a company who got it right for situation like this: Valve (With Steam).
Games have been removed from Steam before for X and Y reason. Meaning you cannot find them in the Steam online store and buy them anymore. But if you bought said games previously, it's still on your game list and you can still download them anytime you want.
This is about complex licensing agreements related to each content provider and relative to the types of software content (games, books, Apps, Music, TV, Podcasts, Movies, etc.) and their licensing agreements. It also may involve laws or requirements, so you analogy is apples and oranges. If the licensee holder's agreement requires Apple to remove all traces of the content (which may include any listing) then unless there is a law stating otherwise Apple must comply.
Also another possibility you need to take into account. In the Steam model you probably have a cloud based storage account that is considered yours and your game is moved to it. A similar analogy is if you were to upload your movie/TV to your iCloud storage account you would have it to download even if it was removed from iTunes.
Apple in NO way benefits from removed content so it is in Apple best interest to keep as much content and info available as long as possible.