I think smartphones have plateaued. The iPhone 5 and Nexus 4, and Nokia Lumia 920, pretty much all do the same thing very good at the end of the day. Each phone, can text, e-mail, surf the web, give you GPS navigation, pretty much the same.
Sure us hardcore nerds can spot the differences in each OS, but to the average smartphone user, there truly isn't radical difference between each of the three top OS's.
What else can truly be done on a smartphone that isn't being done already, by any of the big 3 ? Sure they will get faster, thinner, better screens, etc...but to me all smartphones seem to have reached a limit.
An iPhone 5 or Nexus 4, can do pretty much anything right now. What would a iPhone 6 or Nexus 5 really add to the game, over the current phones ? What's the next major breakthrough that none of these phones have yet ?
No only iOS has plateaued, Android and Windows 8 Phone are innovating, making those "every day tasks" even easier, and putting together a better mobile computer, improving speed, and making it better for real gamers and not just casual angry bird's gamers
But yes apart from that they have plateaued, just like PC's have, but they have been doing they same thing. But remember before around 2006 they had plateaued, just all the same stuff, buttons, a screen, and you could call/text that was it, apart from slow 2G and G connections and maybe the ability to play snake. So the plateau will end, and very soon, with Samsung's prototype devices of YOUM devices, the tablets that close, and the phone that folds out into a tablet, And devices like Google Glasses being announced left, right and center. So the plateau has ended, and I don't believe it begun, they were improving on the devices they had, etc