> 2. Not sure why you are comparing App Store with Amazon when Apple has an equivalent: the Apple Online Store. It does have physical products and has to deal with figuring out shipping across multiple regions. It's actually comparable to Amazon since they both use the microtransactions approach to billing.
Are you serious? The idea that Apple's online store is even vaguely comparable to Amazon in terms of complexity is just laughable. To start with, Amazon sells essentially everything Apple's store does - plus millions of other products too. And unlike Apple, they're tracking a wide variety of promotions and offers over those millions of products. Then we can talk about all the third-party providers that also sell via Amazon. And how many orders of magnitude more difficult Amazon's search problem is. Not to mention Amazon's recommendation engine. Or the order of magnitude more online users and transactions (Apple's user base is in the same ballpark, but how many of them buy online vs in-store or via a retailer or carrier?). And on and on.