I'm sorry but you are just plain wrong on the monopoly part, you do not need a monopoly to be judged to have been anticompetitive.

I might be partially wrong, but definitely not plain wrong. Let me explain:

Eastman Kodak Company v. Image Technical Services, Inc., 504 U.S. 451 (1992), is a United States Supreme Court case in which the Court held that a lack of market power in the primary equipment market does not necessarily preclude antitrust liability for exclusionary conduct in derivative aftermarkets.

Thanks for bringing that case to my attention! I'd never heard of it. Reading the short blurb you posted here was interesting, as was going and reading through the majority opinion itself.

The Apple App Store is almost a textbook example of a derivative aftermarket.

Possibly, but possibly not.

The "Apple App Store" is a walled garden that a lot of people despise, and a lot of people love. But it is a deliberate entity, not a derivative aftermarket.

The potential "derivative aftermarket" is 3rd party iOS apps. And there is nothing to stop anybody from developing an iOS app using whatever API or SPI they wish.

Using private SPI only precludes you from getting access to the App Store, sure. But you can still develop and run the app on your own personal devices without jailbreaking it, and you can also give away the app to a number of other people who have not jailbroken their device, and you can sell or give away the app to any number of people who have jailbroken their device (which is perfectly legal).

This is in stark contrast to the Kodak case where ITS (et al) were actually excluded from participation in repair market because Kodak prevented all reasonable ways of them doing so (not selling them the parts).

Additionally, on the consumer front of "businesses that own and operate Kodak equipment" they were left with a single choice for repairs - Kodak. Contrast this to the consumer front of "iOS device owners" who still have multiple venues for getting 3rd party apps onto their devices.

But the above arguments are merely theoretical; Legal arguments that could easily be made in court if Apple were ever sued under the same terms as the Kodak case. You may not agree with the above arguments, but they definitely make the theoretical Apple case "plainly" different from the Kodak case.

Now to touch on one point that is not remotely theoretical; The actual opinion in the Kodak case.

While Kodak imaging equipment did not have a monopoly, the majority opinion did find that there was significant information cost and equipment lock-in that prevented a user from easily switching their imaging equipment, and therefore Kodak's scheme was predatory.

Quoting from the opinion:

If the cost of switching is high, consumers who already have purchased the equipment, ... are thus "locked in,"

An iOS consumer does not have significant lock-in preventing them from switching their smartphone platform.

If Apple's approach here is ever tested in court, and they lose, and the Kodak opinion is cited at all during trial, I will come back here and eat my words.

But to say that case is exactly what's going on here and therefore I am "plainly wrong" seems quite disingenuous to me.