I don't think things are as clear cut as you make them out to be.
Apple says nobody can run apps on their phone without handing them a 30% cut. No side-loading, no other stores, nothing. There is very obviously a market for apps that Apple controls completely. Just because there are other app stores for other phones does not mean Apple doesn't have control over the entire market for iPhone apps. Markets can be narrowly defined in anti-trust law. Apple is fleecing iPhone users for that 30%.
I don't think there's a good parallel case for this. DRM'd Keurig cups are the closest thing I could think of, but that never went to court that I know of. The case will be interesting: can you create a secondary market that you exert total control over? Can I bar anyone else from selling apps for my phone?
Personally, I don't think Apple should be able to do what they are doing and I hope they lose. It would be a win for consumer rights and free market principles.