I came across an article titled "Why Phones and Pads Cannot Replace PCs". The author insists that PC's will never go away. Never mind that he led with the silly assertion that it's difficult to post a photo to Facebook from his iPad. It isn't - in fact it's as easy or even easier than it is from a PC or Mac, but let's ignore that. His more general theme is that isolating apps for security makes tablets and phones clumsy and inferior.
I'm reminded of the early eighties when pundits were certain that the minicomputers made by companies like Wang and DEC would rule the computer market forever. PC's were toys, not meant for serious work. They weren't powerful enough and lacked the features that business needed.
Of course PC's gained power. Hardware capabilities became stronger and operating systems and apps took advantage of that. Business and individuals drove the features and that is exactly what is happening in the mobile market. The world is changing whether you and I are ready or not. No, I can't comfortably do all my work without my Mac desktop, but I can do quite a bit of it and with every passing year I will be able to do more.
PC's won't die any more than minicomputers died. They will become irrelevant to most of us and are already to some of us. That's reality.