I agree that there needs to be progression. But the idea of re-learning something isn't always a good thing, there needs to be a justification for it.
Example 1: We thought the Earth was flat. We learnt that it was spherical and changed our thinking. This is a good example of change and can be justified.
Example 2: Someone wakes up tomorrow and decides that he's going to walk around on his hands rather than his feet. He tells the rest of the world that this is the way of the future. Are you going to start walking around on your hands, or are you going to point out that it's not as convenient as the method before? This is an example of a bad change and cannot be justified (unless you don't have any legs, I guess).
My point is that not all change is bad, but not all change is good. Microsoft is trying to progress with Windows 8 by creating one operating system for all devices. I freely admit that I think it would work fine on a touch device, but for me it falls down when it comes to the desktop side of things. In order to cater for the touch market they have had to change the desktop side of things, and in my opinion it is not a change for the better.
To add to this, the change from windows xp/vista task bar to window 7s super bar is a good way to introduce new concepts and ideas. It's familiar enough to the older versions that you recognize how it should work (and you can make it work like older versions if you don't like it) but it's also different. Adds new functionality all the while presenting people with new ways of doing things in an intelligent way and isn't forced down peoples throats. Windows 8 is adapt or gtfo.
It's a good example of a change and evolution and it makes you wonder how they can get it so right in Windows 7 and fail so bad with Windows 8.
The bad part is that I want everything that windows 8 offers, just minus metro.