That's a good point of view, and I haven't seen it that way before

I think it just depends on everyone, those (like me) that prefers focus on what I'm using right now, and to have a clean and free workspace might like the taskbar on bottom. (I even create a mockup of an explorer with the menus on bottom ^^)
But those like you that think the taskbar is the beginning and end of everything prefer to have it on the most viewable place, which is on top.
I think both have very good reasons.

But to me the most annoying thing is about the caption buttons. With the taskbar on bottom and a full-screen window, all I have to do to close a window is to put the pointer on top-right of the screen and I'll be sure to be on the close button. But it's impossible with the taskbar on top, where I'll have to look and point directly on the button and not 2mm away. I don't feel comfortable with that.

Windows may be part of the last OS to use it on bottom. I think it will slide to the side for future OS, as I think screens may continue to be more width (why have 2 screens when you can have only one...), and a giant taskbar on bottom or top may begin to look ridiculous with such large device.