Will Oremus wrote an essay on Medium in which he argues that Apple is a monopoly, specifically when it comes to the App Store. I think a few good arguments could be made in support of this accusation. But my opinion lies with this quote:
Apple’s platform is significantly less open than Google’s: Unlike its rival, Apple doesn’t allow any app stores on the iPhone other than its own, and it doesn’t allow users to “sideload” apps downloaded from the web or elsewhere. The company says its goal is to ensure users can trust every app they download; allowing unapproved apps could expose users to privacy violations or malware.
The App Store isn’t perfect, but I believe it contains far fewer malware than Google’s Play Store. Apple’s restrictions also make it better for privacy, and thus better for people. I think price is a better argument than the walled garden. Or, I at least have more sympathy for indie developers rather than billion-dollar competitors to Apple.