Well it depends on what your bar is for a monopoly. E.g. I can only use Comcast where I live. Comcast is not technically a monopoly - I could move somewhere else where other providers are available. But the friction to change is high enough that they effectively are a monopoly to me.

No company is a monopoly if you are flexible enough. Where antitrust starts to become relevant is a bit of an arbitrary line. If you think "mobile phones" is the industry then Apple does not have a monopoly. But there are many people who would put up with a lot before switching from iOS to Android, because of apps, iCloud, iMessaging, or whatever.