There is no disappearing division between devices, there is rather a stronger division between mobile platforms (including tablet and phone) and PC platforms. And that division is only going to get stronger.

Maemo and Meego are dead. Chromebooks are not likely to blow up. If small ARM machines get popular it will be by running some weird mobile-type OS. Native apps seem to be much more commercially attractive than pure HTML5 apps. On the other hand, I don't see evidence that iOS and Android are going to become plausible PC platforms. Netbook sales have slowed way down. All the buzz is about expensive mobile devices like tablets, and expensive laptops, and these two categories are not converging. It only appears that a convergence is coming because mobile platforms are cannibalizing the casual uses for PCs and netbooks.