I recall the same predictions for PDAs in the early 2000s and that they were going to kill the Notebook market for business travelers entirely. Pull the PDA out of your pocket, take the Stoaway Keyboard out and dock the two. A laptop replacement the size of two wallets. It was a great idea, except that it did not overcome the actual need of a laptop.
If you're going to carry around a 13" Tablet + Wireless Keyboard/Mouse, what's the point, just go for a 13" laptop which is all the more powerful, gets just as good battery life, and doesn't suffer from the clumsiness that comes with such a configuration.