Apple will be better off if it opens up the platform. New app stores will have a very hard time to keep the offerings clean and to weed out malicious software. As a result, they will be discredited very quickly and users will return to Apple's app store. The barrier to entry is REALLY high here. Ensuring user safety is extremely expensive to implement across millions of apps. Apple's is legitimately concerned that such outcomes will hurt its brand, but that is a very unlikely outcome. Witness the fact that very, very few Android app stores have survived. Even Amazon quit because it wasn't profitable enough. The optics are pretty good for Apple's app store.