Seriously, the only people who still bring this up (and mod it "Insightful" on /.) are those who are utterly ignorant of reality and just want to gripe about Apple (while ignoring all the other app stores operating under the same terms).
My friend, you are either "utterly ignorant of reality" or intentionally muddying the waters. We're talking about two entirely different things here: 1) buying an app from an app store, and 2) paying for digital goods within that app (or free apps).
Everyone agrees 30% seems to be a fair, market based price for the former. Microsoft's problem is with the latter. Niether Google Play nor Windows Marketplace nor Amazon nor RIM force all developers on their platform to give 30% of everything sold within their apps.
Apple has NOTHING TO DO with providing SkyDrive service to Microsoft's customers, yet they are demanding that Microsoft give them a 30% cut of it merely to have an app on their platform.