That's not uncommon, Valve takes on average a 30% cut on all store sales on Steam along with a cut from item selling on the community markets for skins. Like Apple they can get away with it thanks to the size of their user base and the fact that there is now even a subset of users who will not buy a game, even DRM free ones, unless it comes with a steam key.
I don't see how it doesn't? This was a discussion about a company shutting down, and this particular sub-thread was regarding speculation that the shutdown was the result of Apple 'coming after them' for their 30%... Your comment that it was only for digital goods, while true, required further elaboration that even that can be hard on a business. This comment is directly related to the sub-thread's speculation on why Threadless shut down.