While I am not opposed to the court's ruling, I find the designation of a 'monopoly' confusing. The X-Box is also a monopoly, yes? The Playstation store? What about Ford? What about Wallmart not accepting Applepay? I think it's a very slim slice indeed to claim a monopoly within a single companies product. And if this is upheld I see no reason why a lot of other companies couldn't be forced into a similar ruling.
I don't believe they were ruled a monopoly. Rather prohibiting developers from providing links to their own website and/or even mentioning alternate means of making IAP was ruled anticompetitive. Those rules had to be relaxed somewhat. The way Apple complied with that ruling and then lied under oath about their process to comply basically led the judge giving the plantiffs the maximum possible on that issue. Oops.