Articles like this seem to like presenting a tunnel vision view of the world. The author's little niche works well with a phone and a pile of video clips (I hate presentations that are all videos btw, you get very little actual content out of them), so why shouldn't everyone else's?
I hate to break it to you, but your local bank won't be doing all its work on tablets any time soon. They might augment certain roles with them, but the bulk will still be a traditional PC or similar. The local call center? That'll continue to use something PC-like for a while yet. All those businesses *creating* stuff, will continue to use some form of PC to do that design and engineering work.
There's actually only a very small group of people who could make the move to *just* a phone and tablet. These people being mostly consumers of info, and people who give presentations for a living. As much as I'd love to be able to do my job using a 5" screen, I suspect that my employer would have to hire 3 more people to do the job as well, whilst I'm busy jabbing away at the screen and getting annoyed with auto-correct. Even this post would've taken 5 times as long to enter on a phone or tablet.
Once again, the death of the PC is predicted and once again I think the author is living in cloud cookoo land.