What I think we are seeing here is something like "justifying your existence" or in this case job.
Having thought about the changes in the UI that have been introduced lately, i.e KDE 4 Gnome 3 and Unity, I think that they have basically run out of things to do with the, shall we say, conventional desktops and are frantically searching about for new ideas that will allow them to do "neat things". Unfortunately for them, they seem to failed to grasp what the user really needs, something that launches applications and allow maintenance of the users' system but basically gets out of the way. As they say in cricket "if you don't notice the wicket keeper, then he's doing his job."
I think that Xerox PARC got it right all those years ago, after all if you were to design a hammer from scratch I would put money on it looking like a hammer when you finished. They're just designing solutions looking for a problem.