+1 as always, zhenya.
Furthermore, people forget, it's not about the operating systems, it's about the input devices. I encourage all to watch Steve Jobs iPhone and iPad launch keynotes, all the answers are there. Revolutionary input devices begat revolutionary UI's begat revolutionary computers.
People like to do their office work with a mouse. History has shown this. For fun, I encourage all of these Apple Convertible Zealots to grab their notebooks, unplug the mouse, and build a professional Powerpoint presentation. Then, for extra laughs, try iMovie, try Excel, even sending an Email becomes a time-consuming adventure.
Next, try the inverse. You'll have to use your imagination, but as you recline in a hammock with your iPad and want to read news and listen to music imagine you've got a mouse that you've got to use in the process. Rub it on the ropes, slide it over your legs, try to advance the screens, again just adds complexity.
What MS is attempting to do with a single OS for both Notebooks and Tablets is a smart business move, but it's not optimized for each, its still really just Windows with touch. People can't do office work with touch and people don't want to whip out a mouse on a airline tray table to watch a movie. Children mold clay with their hands and write with a pencil. When they grow up, they do office work with a mouse and navigate media with touch. It's just how it is.
BJ