1. This is not going to be brief. It cannot be brief. A smartphone is at the top end of complexity for celluar/mobile telecoms. As a computing device, it merges all the ability of a modern laptop with far more complexity of the cellular telecoms networking. Cellphones are the most complex electronic gadgets on the planet and mobile telecoms itself the biggest interconnected system and one with the most complicated eco-system, combining not only telecoms (fixed and mobile) but also the internet, banking and advertising, etc. And all of those difficult issues come to head, most strikingly, with smartphones. And now you ask me, why US different from ROW? I will do my best to explain, but we have to do it in parts. And yes, go get a cup of coffee, this will take a while.