Monopoly power is not illegal itself. Abusing monopoly power is. Apple can argue that their App Store should be the only way to sell apps in Apple phones becau

Monopoly power is not illegal itself. Abusing monopoly power is. Apple can argue that their App Store should be the only way to sell apps in Apple phones because security and other stuff. But they can't take huge markup unless they are actually spending most of it into security and providing App Store (they are not). If they drop their cut into 5% or so, and they would 3% of that running App Store, it's still handsome 40% gross margin and regulators would leave them be.