Maybe the most significant article I recently read concerned a remark from Sony CEO Kazuo Hirai, saying he was expecting a follow-up device to the smartphone. He marked a timing of two to four years in the future where such a device could be expected.

That may be correct, although I kinda doubt the eta. I believe that the software concept that is currently dominating smartphones will first have to change drastically for that to happen.

Apple changed the smartphone into a wonderful device, but I believe the software never made the transition with the hardware. Surely there are great apps, but interaction between apps is still very poor. Operating systems barely allow cross-app interactions that would bring the software on par with the concept of the device, being practical, fast and mobile. And although the software coding is getting more and more sophisticated, allowing for amazing possibilities, the platform concepts are still holding back the real breakthrough that would enable the smartphone to evolve into a new superior concept. So the real eta would be 2-4 years after this transition, earliest.

Sources :

http://www.telegraph.co.uk/finance/newsbysector/mediatechnologyandtelecoms/11079256/Kazuo-Hirai-Sony-is-looking-beyond-the-smartphone-for-the-future.html