[Locke1689]

That's not really a fair analogy because, while the Amazon marketplace may not sell iOS Apps, presumably they sell things which compete in the same market (i.e., solve the same problem). The Band-Aid competitors don't literally sell Band-Aids, but they do sell self-adhesive bandages that compete directly with the market for Band-Aids.

[Symmetry]

Are they actually competitors? Band-Aid sells bandages for people and other people have band-aids for bicycle tires. Apple has an App Store for iOS devices, while Google and Amazon have app stores for Android devices... I'm not saying its obviously one way or the others, but it doesn't seem clear cut to me.