The difference is simple : is the product being sold digital or not? Uber is not a digital product. Food delivery is not a digital product. Netflix is a digital product. Spotify is a digital product. Pokemon Go is a digital product. If Spotify wanted to open an App the sells CDs, those would not be subject to the 30% fee. But Apple would also not handle that transaction via IAP.
Or think of it this way, Apple cannot verify the delivery or non-delivery of a physical product. Thus they prefer to allow others to directly handle those transactions in case there is an issue. Apple's skill set is in digital distribution.
Is that arbitrary? Perhaps. But they apply their rules consistently. Kinda like in baseball, you can argue with the strike zone that the Umpire is calling. But it is generally accepted if it is applied consistently to every player.
I understand the distinction, or at least the intent of it, but it's not that black and white, and there are examples where the distinction falls apart. It isn't consistently applied, and that distinction is very difficult to make because lots have elements that are digital and elements that aren't digital.
First, I disagree they apply the rules consistently. I've given this example numerous times and people can never explain it: You can buy a digital gift card for one month of Spotify on the Amazon iOS app without Apple taking a 30% fee, but buying a month of Spotify directly does require the fee. The gift card is delivered almost instantly via email; it isn't a physical product because it only ever exists digitally. It is a digital product, yet there is no fee. Isn't that clear evidence of the "rule" being applied inconsistently?
I'm not even going to get into eBay, where you can buy all sorts of digital stuff without ebay having to pay a fee.
Second, things are not so black and white. Most of the services you listed are a combination of physical and digital.
For example, Uber's main service is connecting independent drivers to consumers. Uber facilitates the communication, the scheduling, and the payment. But Uber does not actually do anything physical; remember, Uber considers each driver an independent contractor, so it is the independent contractor that does the physical stuff. So really Uber's services are really digital, yet Apple does not charge Uber a fee.
The same applies to food delivery. Grubhub didn't make my food, they're just the broker between me and the restaurant. Is brokering a non-digital product? Apple could charge a 30% fee only on Grubhub's fee, and not charge a 30% fee on the cost of the food itself. But they don't make the distinction there.
On the flip side, as a contra example, Netflix's service is providing me with entertainment by maintaining a huge system of servers. Netflix, at the core, is a content delivery network business. Read their 10-K, this is what Netflix considers one of their primary functions. They maintain huge server farms, and install specific hardware with custom software at ISPs to ensure the content streams fast. It would be accurate to say that paying for Netflix is paying to access their hardware content delivery network that hosts movies and tv shows. So while it is digital, it is also physical in a big way.
The distinction breaks down even more when you look at purely cloud storage companies. What is that if not just paying to rent a piece of a physical storage server for a period of time? Is that digital or physical? It's both!
So Apple doesn't take a cut when renting a car for a month (Turo), but Apple does take a cut when renting a terabyte of storage on a server for a month (any cloud app). How do you circle that square?
Finally, I got a chuckle out of the baseball reference. I'm not sure if you're aware, but the entire business of baseball would normally be a gigantic antitrust violation but for the fact they have a specific exception to the Sherman Antitrust Act. Without that exemption, baseball wouldn't exist as we know it today.
