This. Point by point.
Is not about small pockets, is about usability. There IS quite a considerable number of people in the world who has small or not-so-big hands, and operating a big phone is uncomfortable. The reason the more manufacturers are in the phone industry, the less diversity exists in sizes, form factors etc is beyond me. You know? Tablets exists. Even with 3G/4G. Go buy one. I have one. Play my games and watch my full lenght movies in the tablet, but I don't need to carry such a thing like a 6' phone just because of a 2-minute youtube video and quick Clash of Clans game in my coffee break. It's a phone. It's a phone and I need it to do their job efficiently, calling, texting, mailing and web browsing one-handed, and except maybe for the web browsing, the extra size is a big handicap for that tasks.
PD: As some of you know, I have a Blackberry Z10 and hope it lasts long enough 'cause it's size is the maximum bearable for me (and yes, lot of people around me)

Some of you will remember the study Apple did about one-hand thumb reachability in their screens:



For a long time this was the right way to do, what common sense dictates, but I think everybody have to keep up with the times, even when you are right (or have the common sense on your side) because of following the mainsteam and their craziest battle of the harder-better-faster-stronger is always the better, popping up thinks like this and this to "fix" any annoyance. This is the world we are living in today.

Do we have to be alarmed? Well, If everything is going as expected, in a few years smartwatches will be at the perfect size to get rid of the wristband and use it as a proper size phone