That's the benefit of building and protecting a strong brand. HTC for example may sell one specific model of Android device with a camera but who knows it even exists? They don't advertise. They have dozens of different models that look very similar. This makes it difficult for consumers to identify a feature they want, identify the model of device it's available on, and obtain it. Apple traditionally rips down a lot of those barriers by offering a simple, heavily advertised, product line that is easy to obtain.
Fair enough, but the addition of video to iChat in 2003 hasn't set off a video call revolution. It's used, but not too frequently in most circles.
Actually from a 20 year olds's perspective it really HAS set off a video call revolution. Video chat is way bigger than it's ever been and I think you can pretty easily draw the line directly to MB owning college kids. iChat was the first time video chat was easy and didn't look and sound like total crap. Skype's is still a disaster in comparison.
By "most circles" you mean "my circle."
Skype/iChat Video is used constantly by very large groups of people all over the world: expats, and people who truly cannot afford to travel far (developing countries "middle" class, at internet cafes).
Media players, smartphones, tablets, etc. were all around before Apple's take on them, but once King Jobs lets loose with the golden touch all of the sudden the entire product space comes alive. It's a little creepy.