The problem extends well beyond the UI. One of the reasons that many netbooks are moving to Windows is because the perception of consumers who were used to Windows on laptops and desktops was that Linux was cheap in the sense of low priced but also limited because of that. There are many Linux apps that have a UI which can best be described as bare bones. There are many others that are or look unfinished. Few (relatively speaking) are polished, much less magic. This is most apparent in the gaming arena. There is nothing I have found in the Linux world to compare to the current class of Windows games such as Dragon Age Origins or even leading Windows games from several years ago.

I would see the problem as stemming from the FOSS model. Unfortunately, UI development is boring and time consuming. Commercial vendors can devote resources to it in anticipation of recouping their investment in sales. Independent programmers have to be self-motivated. Of the efforts mentioned in the original article, I would see Android as by far the most significant, not because of the OS's UI but because it is attracting commercial development through the app store.