In general, magazines surrender 30%+ of the list price of a magazine in a store. So a $6.00 magazine in the rack surrenders $2.00 to the store and oh by the way eats the cost of unsold magazines. Is the Apple Store more like a Grocery Store sales rack.
However, magazines to promote sales and to gather personal information are willing to steeply discount a magazine sale for a subscription, 1/3 to 1/2 off retail pricing is not a surprise. This is really not a big deal, since if they sold the same magazine in store that is all they would get.
If their main goal is advertising volume, then neither model has income from magazine being an issue. If you look at distribution costs for a magazine, e.g., shipping [and returning unsold magazines] as well as mail shipping and handling to homes, it is hard to see that not being a big cost to the magazines.
So Apple offers no shipping costs, no return unsold magazines, a huge market place, etc., and if a customer elects to subscribe to the magazine [or newspaper], then they pay 30% of the cost to Apple. By the way no financial transaction costs, pure 70% cash in a very timely manner. HHmm sounds like a great deal, EXCEPT
Here is where I think the magazines are going nuts - it is NOT the cost or 30%, this is either a wash or might be a savings, its not getting all that personal information that they can sell to advertisers, not to mention loose and drive consumers nuts with identity theft.
So Apple is saying you business model is not messed up on subscriptions costs, advertizing, etc. in fact, the potential audience is huge and this is super convenient to buy, but rather your model of getting and using personal subscriber information will be diminished. Perhaps bad to magazines, but in my mind really good for subscribers.