This has always been Apple's unwritten mission. At all costs, to maximize profit from the premium market segment of any market they are in. Even if that means settling for a smaller market share, even if that means reducing consumer choice, even if that means shoehorning consumers into a "one size fits all" solution...
*SNIP*
Steve Jobs is ultimately one of the very few people in this world who truly understand the potential of eCommerce. But more importantly, he intimately understands his customers and knows exactly what to do to get them to buy what he is selling, and how to keep them coming back for more.
I think it also bears repeating that their business model with iTunes has always been to use it as a way to tie users into an ecosystem where you're more likely to remain an Apple customer. The iTunes store simply does not make a lot of money. If I recall correctly it lost money for the first few years.
Apple's greatest strengths are that it does create good products and is good at marketing products. I know a lot of people will say the "good products" part is blasphemy but it's true. Apple is not a great innovator but the company has a lot of engineers and designers who are great at integrating technologies into a cohesive whole. It's not an innovative company but it's a creative company if that makes sense to any of you.
Making a good product isn't all there is to business. You have to market it and Apple is great at that too. We've all seen advertisements that make you go "WTF" from other companies but a lot of times, Apple's ads will pull you in even if they are not 100% factually correct or insinuate things that are not true.
What about user who is already a subscriber, but decides to re-subscribe through in-app subscription? Apple is forcing the content provider to offer the same price either way, but just because the user decides to use Apple as payment method, it wipes out all of the provider's profits on the content.
Also, take two distributors, both buy content for same price from a publisher. One decides to stick with Apple, and has about 50% of users on iOS and 50% not on iOS. To get 15% profit margin, it would make 0% profit of iOS users and have to make it up by making 30% profit off non-iOS users. Second distributor says, screw Apple, its not making me any money, and underprices the first provider on Android by only charging 15% markup over publisher's price. First distributor can't match this because then it would be losing money on iOS sales. Non-iOS users flock to the second provider, leaving the first one with mostly iOS customers. To make same 15%, margin after Apple's cut, it would then need to charge 45% markup over the publisher's price. Soon you will see a division between companies that only target iOS users, but are forced to charge 30% more to keep same margins, and other companies that only target non-iOS users. Since as an end users, I have no interest in paying 30% mark up on same content, I would avoid iOS like a plague and stick to alternatives.
Streaming products aside, such as Hulu, Netflix, and Rhapsody, most subscription products are newspapers and other periodicals who depend almost entirely on ads for their profits. That 30% is not as bad as it seems on the surface.
The good part for consumers is that Apple wants to try to guarantee the prices for subscriptions on an iOS app is the same as elsewhere. The bad part is as you mention, prices might get hiked universally.
As for developers (content producers really) saying "screw Apple" and not making an iOS app, they've always been free to make a web based version that can be viewed on any mobile browser. Assuming you're a periodical. And there are already streaming apps on the iPhone. Some of which are subscription based. You just have to go to their website to sign up for a subscription.
The fact is developers feel there is a segment of users that they can cheaply sell their subscriptions to. They want to use Apple's storefront but they're balking at the rent. This is no different from Amazon charging a fee for selling through Amazon.com. If you don't like Amazon's prices, you're free to set up your own website/storefront. Keep in mind that Amazon (like Apple) has a large user base that's just waiting to be tapped. If you start your own store, you'll be hit with all sorts of problems and costs that would be reduced if you had gone with Amazon.com (or iTunes).
One thing that a lot of people probably don't realize is that even before the cost of maintaining iTunes is factored in, Apple does not fully receive every dollar that is made through purchases on iTunes. Every business that accepts credit card transactions needs to sign up with a credit card processor. These credit card processors don't work for free. Depending on card type as well as business standing, there is a processing fee that can be anywhere from 10 cents to over 30 cents per transaction. Then there is another fee that is charged based on the overall monthly transaction amount. I forget the exact percentage amount but even at 1%, it can be a staggering payout considering the revenue of iTunes. And that's before they even get to maintaining the iTunes infrastructure.
The content providers do save some money in not having to pay processing fees if Apple is the one doing the collecting so it's not a clear cut 30% loss to the content providers. That doesn't mean I don't feel 30% is too large of an amount for subscription services though. A $10 monthly subscription is at least a $2.50 loss to content providers after factoring in processing fees. A 10-15% charge by Apple is probably the most reasonable. A 30% fee is just insane.