> Sure, the plaintiff may not agree with Valve's 30% cut berceuse they find it too steep, but unlike the iOS/Android marketplaces, Valves is not a monopoly marketplace in the PC space. There are other competing marketplaces they can go to like Epic, Windows store, GoG (which most likely also charge 30%)
Epic charges 12%. Microsoft Store revenue split is, maximally, 100/0. For games, 88/12. Microsoft also, for years, paid you to make apps, even basic ones.
Epic Store isn't profitable, billions of dollars burned since its creation.
GOG split is actually worse in some cases.
The 30% cut is great, in Steam's case.
Like the Android and iOS marketplaces, there's sufficient value add and plenty of alternatives, so there's no reason an antitrust complaint really makes sense. In Android's case, there's the MIUI store, the Huawei store, Baidu's, Samsung's, Tencent's, and VIVO/OPPOs, and that's barely even getting into it. Since the start of the platform, manufacturers have been shipping alternative app stores.
In Apple's case, there's Cydia, AltStore, and I've even seen a few Chinese sideloaded app stores that seem to be able to do some crazy things, like on-device IPA signing. That's not even getting into the most obvious option: PWAs. It's also not getting into the fact that Apple, as a minority vendor of smartphones in America, definitionally has no monopoly. Unless, that is, your definition of monopoly is ridiculously narrow.