The subject of whether there's any future (or present, for that matter) in the notion of "Linux on the desktop" as something that "regular end-users" might want to take up has been discussed in a variety of places this past week. I put my two cents in over on my other blog (and this is "GNOME-related", so I don't want any whining).
The situation, as I see it, is that, even if Linux isn't "dead on the desktop", if it were, it would scarcely make a ripple on the awareness of most users of personal computers.
The reasons why things got to this point, and why we can expect the same in the mobile space—more Android and webOS and the like on phones and tablets and such, but scarcely any user-visible "community developed-and-maintained" open source—in the foreseeable future are really pretty basic as I see it.
Most of this is not appreciably different to things I've said at "GNOME Mobile" meetings and on the gnome-marketing list. If you keep doing what you've always done, you'll keep getting what you always got.