1991-C4 said:
About the only app that could be weighing down the app store is iBooks. I think everyone will admit that it is an abysmal failure and I wouldn't doubt for one minute they are losing money on it. While the app itself shines above most others as an "eReader", people are just not buying books from Apple. The Kindle app is average at best, but no one can touch the breadth of their content selections. A Chevy that runs will beat a Cadillac stranded on the side of the road!
iBooks lead to no looses on Apples side if they don't sell ebooks. It is just an app, if people use it to buy, it generates revenue, if no one uses it, then no revenue, but also no cost apart from developing it.
The main cost for Apple is indeed bandwidth.
Here is a quote from another news site:
'I sell my apps, around 20Mb of downloading data, worth 0.99c. However due to a huge number of apps, it’s too hard to sell a copy of this app.
In order to sell an app, I have to make a lite version which is also around 20Mb for free download. And the download ratio is 100 (lite):1 (full), which means 30cent for Apple cost it 2Gb download bandwidth.
When I made an update (of course it’s free), the same bandwidth cost for Apple, without any benefit.
Nowadays, some apps go free for some days which cause nearly a million free download, it just cost too much for bandwidth but generate no money for Apple yet.'
And the corresponding article:
http://www.cultofmac.com/apples-app-store-itunes-popular-not-so-profitable/27864
Also take into account, that credit card companies get their own share as well, which is another 2-5%.