no one is arguing it has a monopoly on mobile phones, the argument is and has always been that they have a monopoly on the ios software ecosystem they've built.
Yes, but from an anti-trust perspective, 'a monopoly on this thing I built' isn't an issue - arguably every company has a monopoly on that. It becomes an issue if 'this thing I built' captures an overwhelming economic sector, to the extent that consumers have no choice.
Currently consumers do have a choice - and more chose Android than Apple.
At the point where there is a threat to the Android ecosystem, with the possibility that app writers, consumers and handset manufacturers are forced to quit the platform because it isn't viable.
Currently consumers do have a choice - and more chose Android than Apple.