When something goes wrong on Ubuntu for example, the advice is 99% of the time to open a terminal window and start running commands. This is impractical/unworkable for the majority of users.
Ubuntu might be the most forward thinking Linux distribution in terms of ease of use, but for every step forward they take two steps back.
With Unity for example doing relatively "simple" things like configuring the firewall have seemingly disappeared (as well as much other settings). They seem to have just deleted the majority of the UI and said "we'll just use search for everything!" Without thinking through discoverability.
I think Linux is great as a server operating system. But the people behind it just aren't capable of thinking like "normal" users and thus are completely unable to produce something for those users to use.
Right now the most likely contender for a Linux desktop is some kind of Android fork that extends what Google has managed to accomplish to a larger hardware set (or just take Chromium and expand that).
> Linux is not yet "ready for the desktop," and I'm doubtful it will ever be—at least not in the sense that an average person could use it full-time without any assistance.
By this definition, Windows and Mac OS X are both not ready for the desktop. I have had "average people" come to me and rely on me for assistance with both (especially Windows) many times.