It seems that this article at arstechnica.com about KDE misses the point about whats going on the GNU/Linux camp, in a sense that it's not about the kernel itself. It's about the desktop environment.
What's going on, is that there seems to be a race toward convergence. Trying to have an user interface that's pretty much the same on the PCs, tablets and smart-phones. On the GNU/Linux camp, the main example that come to my mind is Canonical's Unity user interface.
The main debate it's about how best convergence can be achieved, or if something that can be done. Some argue, like KDE's Aaron Seigo at this article at themutk.com, that convergence isn't coming at all.
Even though I'd like to see full convergence across all platforms, I agree that it wont happen. In a sense, I think that we'll have some level of convergence. Yet, that convergence wont be on the user interface, but on the standards used to run software so we can actually run our files on all our devices.
The main reason that I don't thing that the user interface will be the major point for convergence, is because the way people interact with each type of device and the use we give to each of them. No matter how much people argue that smart-phones, or tablets, will replace PCs or laptops they wont. We use all our devices in a different way, though there are some aspects like listening music or watching videos where we use them both. But even then, we don't use them the same way.
PCs, tablets and smart-phones are great tools, but each has its place. Most importantly they aren't really competing with each other, but they complement each other to help us do what we do better. We don't have to choose one of them, but we can use the ones that better combine to help us do our best.
In some ways, convergence is already here and we just need to make it work for us.