I don't think "monopoly" means what you think it means. Or "abuse", for that matter! iTunes is a rapidly diminishing factor in Apple's profits, much to their chagrin. People just aren't buying music (like they used to) anymore. Instead it's subscription services instead, which is why they bought Beats last year, although they really haven't done much with it yet.could also be their abuse of their iTunes monopoly still has people locked into eco system.
Oh, and Android apps run on iOS, Winphone devices...?