Target market. Is MacOS a viable target market for Fortnite? Even if you do wish to play competitive games on MacOS... Using the same hardware, the performance has been shown to be worse, in every comparison I've been able to find.
While I think this discussion is moot, as you're claiming this is a reason to start charging for IAP in MacOS apps and Epic has decided not to release new Fortnite seasons on MacOS, because of their beef on iOS, you're also talking about a specialized and high profile game, where most IAP are targetted at mobile specific games. Just look at the backlash that Diablo Immortal is receiving right now. Non-mobile gamers complete reject the style of monetization in mobile games.
Again, is this something you actually believe is true? Apple execs are looking to monetize their desktop OS as a mobile OS? Microsoft is already very carefully trying to do this and it's being pretty unsuccessful. There's a lot of rejection for this aspect of Windows 11. Remains to be seen where it's going to be in 5 years, but for now, I don't think this is where desktop OS's are going.
Back to the real meat of the article, Apple is both doing it's customers a service and a disservice at the same time. What is the solution to that? Let 3rd party app stores on, so that we can go back to no protection against tracking and a store full of garbage? (looking at you, Google Play)