Perhaps you should look at it in another perspective. Windows 7 is finally moving business off of XP in large numbers. Win 7 is stable, well liked, has good driver support, and has a interface that is easily learned by the millions who have been using Windows in business environments since Win 95 debuted. This is the operating system that Microsoft expects business to use now and for the foreseeable future for desktops and laptops, perhaps even to its end of life in 2020.
But anyone who is looking ahead in computer trends knows that we are gradually moving to more portable devices for many of the day to day tasks, slightly more in home use now, but it is also becoming a force in business environments as well. Microsoft has to do something to make themselves relevant in this newer market, and Windows 8 and Windows RT are their solutions for this. By giving users an interim operating system that will work on both their older systems and in the new portables that are being developed, Microsoft hopes to remain dominant and offer their customers some hands on experience using this new type of interface.
As we become more accustomed to the touch screen interface in portables, and learn how to use the desktop within Win8 with more traditional mouse and keyboard, Microsoft intends to wean us off the older style and be ready in 2015 for Win9, which I predict will again look nothing at all like Win7 and the traditional MS operating systems of the past.
Personally, I don't like the looks of Metro in the slightest, and wouldn't have much use for it on my desktops. I doubt I will stray from Win7 without some major inducement...say $50 for an upgrade version of Win8. And even then it better have some major improvements under the hood to make me endure Metro.
But if we are considering tablets only, I think Microsoft's new operating system might tempt me to dip into those waters. But they will have to compete with Android in price and features of the hardware. Microsoft is somewhat at the mercy of their hardware partners in this.