By your given definition, Google isn't a monopoly either as there are clear alternatives to them in every sector that they are in.
If we compare Google's marketshare in end user email, video hosting and search, we can see Google is a lot stronger in many markets, than apple is in their best market.
(I wish I could use an iPhone, but having to use Mac OS for development is a real turn off, considering how sucky Mac OS, in my view, has ever been.)
Buying a mobile for your personal use means you have to develop for it?