If iOS had 100% share, you probably wouldn't say it doesn't have a monopoly on apps because you can just use desktop apps instead.
I also wouldn't say Comcast doesn't have a monopoly because they only have xx% share and you can move to a different state or country and get another provider. Or use your phone for internet instead.
> Ease of customer switching argument
This is confusing the consumer market for smartphones and the markets for distribution of smartphone app.
> Supply-Side Price elasticity argument
Yeah, if any monopoly's cut is too high, you can exit the market. This is not an argument that the monopoly is not a monopoly. This only means there is a limit to the monopoly's power.