At the bottom the article links to John Gruber's "Ronco Spray-on Usability" article, which also provides a lot of background on the challenges of good interface design.

In the original article, I think the most important point is number 8 - "Scratching their own itch." I can see how programmers interested in, for example, having a stable and scalable web server would work on Apache. I don't see the same passion coming from a human interface designer to fix, for example, the horrible user interface for joining wireless networks on desktop linux.

In my opinion the only way the user interface will get fixed is if Ubuntu or another distro pays for expert user interface folks to fix UI issues. I don't see the volunteer community being up to the task.