> My point is that we can get to a point where the only way Apple can actually enforce such a rule consistently is by forcing itself into the process of purchasing physical goods and dictating what physical goods can and cannot be sold.

Okay, you forced them into having a rule about an exceptionally niche category of physical goods. They already ban the sale of firearms, so this isn't even new. It causes them no problems.

> More importantly: the more Apple tries to react to these tactics, the more evidence in favor of Spotify's case. It's a classic case of squeezing sand so hard that it slips through your fingers.

Not when they're so obviously looking for a loophole. It would hurt Spotify's reputation more than Apple.

It's not that niche of a category, though. Any sale of a physical good with a warranty or separate registration process or "cloud" features or any other non-physical good/service that's tied to that physical good would be caught up in this. That's a pretty broad category.

Even if we wanted to stick to a narrow category of "subscription to a service that entails shipping physical media devices on a subscription", there are other apps in that category (though I don't know if they do let you actually sign up via the app): https://itunes.apple.com/us/app/dvd-netflix/id1169772776

Spotify could do something similar and pivot into the music rental business, kinda like an inverse Netflix. Whether that'd actually be better than just paying the 30% App Store tax is another question, of course :)