Apple has a monopoly on operating systems for Apple mobile devices and on software distribution for Apple mobile devices. Apple is using its monopoly in that market to obtain a monopoly on in-app purchases—unlawful tying.
Apple's response, of course, will be that the relevant market is actually software distribution for mobile devices generally.
Epic's battle is undoubtedly uphill. Antitrust law has been weakened nearly to the point of irrelevancy by the success of the Chicago school of economics. Tying arrangements aren't per se unlawful. Epic will need to show Apple has:
- Market power in tying market and status of competition in tied market
- Anticompetitive effect is plausible
Overall, I think Epic probably has the better case against Apple—Apple's conduct is anticompetitive and ultimately hurts consumers, who have no choice but to pay more for IAPs and would, under Epic's arrangement, have the option to use either Apple's IAP system or Epic's purchase system for in-game items.
They are taking a huge gamble that Apple’s position will not stand up in court. Apple in turn is ready to fight this in court to the death. If they caved in to Epic, they lose a lot of money because other developers will ask for the same. If they lose in court, they are in the same position of having to give developers more money.
Epic have forced Apple’s (and possibly Google’s) hand and are very ready to go to court to protect their 30%. The timing of this along with the banning of xCloud and the anti-trust hearings is no coincidence. Companies like Spotify also have legal grounds to go at Apple for being anti-competitive.In everyday logic it is “my platform, my rules” but legally, it is a whole other game.