Yeah, thank you, that was my original point too, which must not have come through very well. Yes, Apple/WalMart gets a cut of the product they put on their shelves. But I would argue that they shouldn't get a cut of a product a customer was driven to from that original product, unless the new product was also heavily reliant on the App Store / WalMart shelf to sell it.
The WoW analogy is an interesting one, because I think it could be argued either way. For instance, if WoW was an iOS-only app, you could probably argue that Apple should get a cut of those subscriptions, since without the app, the subscriptions are not sellable. But what if WoW was an iOS app, an Android app, and a Windows 7 app, and in their iOS app they wanted to link you back to subscription options sold through their web site which were equally applicable to any platform you chose to run WoW on? Why should Apple get a cut of revenue that no other platform provider gets, in that scenario?
As I said before, there are lots of shades of gray in there. A blanket policy could end up hurting or discouraging a lot of businesses that really shouldn't owe Apple anything more than the costs they've already paid them to utilize the App Store.