I think it's still too early to say what will happen yet. Funnily enough I think small form factor devices such as tablets will eventually eat into the PC market with desktops remaining only at the high-end. Tablets have the advantage of being like a proper PC that you can take around anywhere. All your files would be in one place. Call me one of those crazy tablet people, but hear me out first.
First of all, I don't think tablets will take over the market overnight, and I think some OSes (*cough* Windows 8 *cough*)
are trying to force this on us too quickly without any real thought to how this should happen. I believe that nature should take its course here.
There is one major hurdle to confront before I think small form factor devices can really take over. I simply don't think any OS is ready for this yet. We have the likes of Android and iOS that are built specifically for tablets and phones, but they don't function well as a PC interface. I guess Windows is heading in this direction too as Microsoft want to eventually phase out win32 in favour of winRT (unfortunately regressing when it comes to desktop use). I don't think that 'one interface to rule them all' is ever going to work.
An ideal OS in my mind would be one that is open and one that adapts to the different input devices that are plugged in. Let's say you want to use a tablet on the go (would be pointless otherwise
). You would get an interface suited for touchscreen. Everything would be fullscreen because it's a bit cumbersome to use a desktop paradigm on a small screen with touch. Of course, things like office applications won't adapt well to this, but when you use a device on the go, the most you want to do with an on-screen keyboard is simple note taking. Now, you bring the tablet back home and you want to do some serious productive stuff. A small touchscreen isn't going to cut it. So you plug in a proper keyboard, mouse and a large monitor. The OS adapts to that and the interface reverts to a more traditional desktop paradigm. Now you can use it as a proper PC. Perhaps to make that step easier, there could be some kind of docking station with the monitor, keyboard and mouse already plugged into it. All you would have to do is plug the tablet on top of that. Power users would probably want a proper desktop with a bit more horsepower, but for most people a tablet would be fine if it could do this imo.
Anyway whatever happens, I don't buy the idea of this whole 'post-PC' nonsense. The PC I believe is here to stay, and that includes a traditional desktop interface when needed. But that also includes smaller form factor devices too.
LMDE (tracking Testing) with Cinnamon; Intel Core 2 Duo E8400, Nvidia GeForce GTX 260 (using Nouveau)