Google controls the platform and they're the ones who set up scary warnings for installing apps via sideloading (despite malicious apps being not uncommon in the Play Store itself.)
In this case, the leveraged market is the app store, and the restrained market is mobile payment processing.
My friend, does Lyft take Mir as a payment method? Can you choose to use Stripe to pay for your Airbnb (vs. their in-house processor)?
I really am curious about the legal precedent you're relying on - when has a marketplace ever been found to be acting anti-competitively by choosing the payment rails they use?
No, it's preloaded on every device, that's why.
If some other App Store, 'App Store B' were preloaded on every device, and App Store were not, then that 'App Store B' would ultimately be 'that much better'.
That said - I don't agree with Epic here.
If you want your merchandise in Walmart, it's fair that Walmart does the selling and the checkout. You can't put your merch in there, and expect to be able to buy it 'online' and walk out with it. This is irrespective of Walmart's position in the general market.
Google Play preloads are another question.
Sideloading is also another question.
But stuff in Google Play, I think it's fair if they set the rules there.
Did you enjoy your Fire phone, because that's exactly what you're describing. Somehow people decided they did not like it...
You’re conflating some ideas here. A marketplace owner always has “dominant market power” over the market they own. That’s the nature of marketplace, the owner gets to set certain rules like the types of payments accepted at the marketplace, because that is literally the job of a marketplace.
Google also has dominant market share, since their App Store is the best for android, but that’s legal (keep in mind Amazon, another $1tn company actively competes in this space) - the government does not want to force consumers to use worse app stores. Competition for the sake of competition is not pro consumer.
What Google probably isn’t doing (and what is illegal) is using its OS market power to crowd out other app marketplaces. As mentioned above Amazon meaningfully competes in this space. The closes you could get there is Google doesn’t publish its own apps to other app marketplaces, but that’s likely not across the bar of anti-competition.