In a few years there will be 2 billion laptops and desktops in use around the world. Don't know why no one bothers to mention this. It will take a minimum of many decades, perhaps a century or more, to transfer the work human beings do on them to something else. Even then they won't be eliminated.
It's like saying in the 1500s, in five hundred years people will not be using boats.
Normally I don't comment on this site anymore, just casually scan an article I randomly click when I'm bored because this is one of the shortcut tabs in Chrome I'm too lazy to delete. I do this because I don't seem to be the right age/knowledge group here, and there's nothing wrong with that at all for this site... I'm just not an eager-to-learn-this-sweet-stuff highschooler anymore, and not a 40-70yo still-staying-up-to-date user either. BUT I used to be the eager-to-learn highschooler, because this (IT) isn't just my career, but my complete and total passion.
Having said that, my homebrew/personal passion side occasionally feel too much of an urge to hold back on some of these statements, and this is one of them. I really have no idea how you came to the conclusion that it could take 'decades to centuries' for us to translate desktops/laptops to tablets. The thing is, I agree with you, it's a ridiculous leap and tablets and laptops both suit their own specific types of markets, but neither can do the other's job perfectly. It's like when car manufacturers try and put trucks and cars together, they always come out looking retarded or completely impractical. But think about this- in 1983, just a few years after videogames took off- the world thought that fad was over. 2 years later it blew up again and never stopped. In the 70's, no one but the nerdiest of nerds ever thought computers would be practical or necessary enough to fit- or be needed- inside a home. In 1993, cellphone's were only inside cars and toted around by rich guys. In 2006, touchscreen/smartphones were still such a niche market no one would have expected something like the iphone to make them a mainstay in the hands of almost everyone on the planet. In 1994, the internet or 'web' was barely a term anyone had even heard of, and by 1996 everyone was trying to get connected. 10 years ago that '2 billion' figure you mentioned was probably less than a quarter of that. If you told everyone in 1900 that they'd be driving around in self-powered cars in 10 years, they'd look at you the same way you'd imagine those 'tell people in the 1500's they wouldn't be using boats anymore' statement was. If you get past that, I mean look at how quickly the entire world can adopt even useless stuff if it's marketed correctly- remember Kony 2012? Within 2 weeks the entire world knew his name, and 2 weeks later everyone forgot just as fast.
So I agree with you that it's absurd for Microsoft to be trying to push this like everyone's gonna adopt it and it's the clear way to the future, because it isn't an evolution of computers... it's a totally different type of computer. And tablet OS's/technology has been trying to be pushed for about 20 years now too (just like 3D technology's been trying to get pushed since the 50's). But I don't agree with your logic behind that opinion, because if tablet tech WAS actually practical and capable of doing everything PC's do now, just in a better way (like, say LCD's replacing CRT's, that incorporated everything from old tech and fixed all the big the disadvantages it had), I'm quite confident the world wouldn't have any problem adopting it ASAP. It's just a stupid technology (when compared to conventional computers), and Windows 8 is a retarded approach at trying to force people to adopt it.