Re: I wonder why Apple customers don't sue for such things
"I mean when you buy something, it's your right to use it in any way you want.". The trouble is, you don't buy software - you licence it. And the licence says what you can and can't do with it. If you don't like the term of the licence, you return it and if you don't return it, your agreement to the terms is implicit.
Also - sue over what? Go ahead and do whatever you like with your iDevice - if you want to wipe it and install Linux on it, go ahead. It might be difficult but you can't sue for that. It'd be difficult to fly to the Moon on it too, but that's another thing you can't sue them over because you think they should have provided that option
You're getting confused over between Apple making it hard to modify the software on their iPhone (which is the reality and which they are entitled to do) and your fantasy of Apple having to provide an easy option for users to do/install whatever they like.
I'm not defending Apple here - I'm just clarifying your thoughts :-). Try it with an Samsung device - you bought it, so it's yours to do what you like with. And if you can't reverse engineer & customise their proprietary additions to Android and install them on your Nokia or sell them on the Google Play store then is that something you can sue them for too?
You can't sue someone because something you bought won't do something it wasn't advertised to do.