Clearly, touchscreens are the future of computing - Star Trek says so.

But seriously, I can see tablets one day replacing laptops and desktops for a lot of "consumers". Power users, developers, IT and business professionals will still need traditional interfaces for a while, until the new touch interfaces are more refined and flexible. Windows 8's metro interface is not there yet - but it's decent enough for casual computer use. And for gamers - it hardly makes a difference as games are mostly played full screen anyway.

I think Windows 8 hasn't gained traction because relatively few people own tablet PCs or touchscreens (aside from iPads and Android devices).