You are ignoring the relevant market. Sure, Google and Apple are competitors in the smartphone market (where they have a very dangerous duopoly, but let's leave

You are ignoring the relevant market. Sure, Google and Apple are competitors in the smartphone market (where they have a very dangerous duopoly, but let's leave that aside). But they each have a monopoly in the software distribution market for their respective platforms. Additionally, Google has a monopoly position in the smartphone OS market: if you want to build a smartphone, Google Android is basically the only option in town (Apple doesn't sell or license iOS, so it's not a competitor at all in this market). Additonally, Google have used their position in the Android software market to cement their position in the smartphone OS market, and vice-versa. For example, they de-list certain apps from Google Play Store is they are offered on certain competitor stores (notably, Amazon's). And they don't allow Google Play to be installed on a phone that doesn't ship with it from the factory. And there are numerous other examples. Plus, they've been foolish enough to discuss a lot of these strategies internally over email as ways of ensuring competitors don't succeed, which came out clearly in the discovery process.