The idea of "the death of the PC" is just that -- it's an idea. It's a hook that, if you believe in it (and I do), it can be quite informative about what seems to be happening to the PC industry, and the wider computer industry in which it sits.
But most people do not like the complexity that comes with power and flexibility. Some people just want to give their parents a box that lets them have a video call with the grandkids from time-to-time, and don't want to have to futz around configuring anti-virus software.
The reason why people buy smartphones and tablets isn't because they are necessary better or more worthy than PCs. People buy them because they now have the option to -- i.e. they can.
Go back five years and there was no choice. That last example of grandparents Skyping the grandkids -- that would have needed a PC. Now it can be done with a free-on-contract smartphone. Or an iPad, a Nexus 7, Kindle Fire, etc.
Surface RT was, by design, a good enough post-PC device implementation to compete with iPad and Android in that post-PC market. It ticked enough boxes to make a good showing -- certainly more boxes than Old Windows did.
But we know that Surface RT, and Windows RT has failed in terms of numbers.
More importantly, Surface RT also failed in terms of philosophy, taking the whole of the Windows 8 Project with it. The principle of the project -- namely that the post-PC was getting it wrong and that people were desperately after a "PC Plus" -- has now been shown to be flawed.
Did we all just witness Windows start to die? | ZDNetMicrosoft has to stop selling Windows as a competitor to the iPad, and start selling Windows Phone as a competition to iPhone and iPad, and also as competition to Android smartphones and tablets.
Or to put it another way, if you're looking to compete in a market of oranges, maybe go out there with oranges, rather than try and convince people that they actually want lemons.