Well, not really, because you could use android, and it commands 70% of the global market share

Also, the way the law is, you have to have both a monopoly & also be causing substantial harm to the public. I.e. you can have a monopoly if it's really nice and more like a public utility. So after the Microsoft antitrust case (for basically same thing), it's been very hard to justify breaking up tech companies or banks

If a company acquires its monopoly by using business acumen, innovation and superior products, it is regarded to be legal; if a firm achieves monopoly through predatory or exclusionary acts, then it leads to anti-trust concern

For example, business can defense that its business conducts bring merits for consumers

(Wikipedia)

What happened with Microsoft browser tie ins antitrust?

Ultimately, the Circuit Court overturned Jackson's holding that Microsoft should be broken up as an illegal monopoly. However, the Circuit Court did not overturn Jackson's findings of fact, and held that traditional antitrust analysis was not equipped to consider software-related practices like browser tie-ins

So in short, Apple's legal / business strategy here is totally solid. Arguably helps users, defended by precedent, and doesn't dominate market share. Of course they have to debate all this