The main reason could be that they don't have a competitor in UNIX devices at the moment, at least when it comes to hardware quality. Beside that, if you want

The main reason could be that they don't have a competitor in UNIX devices at the moment, at least when it comes to hardware quality. Beside that, if you want to do mobile development, you need a OS X at hand, again, not much alternatives. All companies have a life time at the end, and I think Apple is enjoying its 90s of Microsoft era.