You can end up in a monopoly position without a fault of your own. Once you are there, you are no longer free in your business decisions. Simple as that.
Sure. But it's not clearly a monopoly position. People CAN buy apps, music, books, etc. on other platforms at prices better than what Apple charges. But, they avoid doing so in massive hordes.
Option #1
I can go with iOS and pay 30% fee to Apple. At the same time I can still sell the same content elsewhere but at the price inflated by Apple fee.
Option #2
I can go with Internet, Android, PalmOS, RIM and WP7 platforms and pay no fee whatsoever.
Considering that the market share of iOS devices among all mobile devices is small and shrinking, the choice is quite obvious.
I am afraid that this new subscription is DOA. It will be only good for such content providers like "iOS Magazine".
You're looking at the wrong marketshare. You need to look at who has the biggest percentage of people actually willing to BUY stuff. Android owners, RIM, blackberry, etc. don't actually pay for content.