It's not Apple charging 30% itself that is problematic it's that no other option is allowed and they then force things like 30% cuts or policies of what apps are allowed with that. Other launchers/stores (or none at all) on PC succeed but that doesn't mean there can't be a popular option that still takes a 30% cut. A most popular option also does not mean that option has sole discretion on what is allowed to be installed on PCs, just what is allowed on that store.