Earlier quoted context omitted.
I applaud Mark Shuttleworth and his vision. Sadly we're missing "something else" other than Mark Shuttleworth. What he does, is what most others are doing in a half-hearted, compromised way: providing a "packaged" system that works without much hassle and which is based in pretty much the same interaction principles of the 70s and 80s. Being Open Source, Linux could do a lot more than that. But nobody explores these…
I am fascinated with the idea of customizable window managers. I haven't delved that deep, but the difference between XFCE and Unity is night and day. I can choose color schemes, window decorations, and make custom task bars. This should be table stakes for graphical interfaces.
Also http://awesome.naquadah.org/ and https://code.google.com/p/wmii/
And that's just windows management which is probably the most obvious advantage of an all-open approach, but there are other things like user programmed priority systems, memory management etc which could potentially do a much more effective usage of the hardware than the standard monolithic opaque approach.