I would be really surprised by that. The gross 30%, presuming it always applied, would be about $6 billion per year, which would be an enormously expensive online store. Of course Apple's cut is often lower than 30% -- I can frequently buy $100 iTunes cards at Costco for $80, for instance, and then add that the retailer surely gets a cut as well.

Nonetheless, the iTunes empire is currently doing almost $20B of business a year, with a $6B cut. The NFL, in contrast -- for all its seeming enormity and influence -- is about a $8B business, gross.

"According to Apple".

I don't think we've had anyone actually analyze that yet. It's only Apple that's been telling us that they barely cover the running costs. Also that was years ago. I imagine at least some profit grows faster than the costs with more apps in the App Store, more streamlined review policies, and increased profit/app from IAP business models.