So this is one of the few times I decide to get political and/or rational. Most of my career has been spent on Linux. And while the gettin's good, I don't subscribe to the notion that Linux, as a desktop, will take over the World.
Let me make one thing clear. I do believe Linux, as a core, will succeed in many forms. On the server, on mobile products (where it is the core and not exposed directly to the user, a la Android).
So here's the problem as I see it. Too many choices. Yes, this has been beaten to death, and to some extent, many Linux vendors have taken note. Debian used to be a free-for-all where all of the choices were exposed to the user. People who used Debian loved the choices, but the fact isn't that they loved the choices, they just loved that their choice was among them.
If you didn't have a preference, for example with a Desktop environment, then choices are bad for a user. They didn't know how to pick one. So now, there is a default. That's great, but across many Linux distributions, even if the default is Gnome, the little nuances of each system will overwhelmingly differentiate the entire thing so that no Gnome desktop is truly the same as another distribution.
So why are choices bad? I want to take an example from a book I was reading recently called The 4-Hour Workweek. It tells of a watch company that wanted to advertise in a magazine. The watch company had many different styles of watches and wanted to put a full page ad that showed off 6 of them. The advertising executive said they should pick one watch and show off that one. To settle the dispute, they had two full page ads: one with the 6 watch layout, and the other with a single watch. Don't you know that the single watch ad out-performed the 6-watch ad by a factor of 6? Interesting...
So anyway, choices are bad for consumers. They would rather have one choice, even if it may limit them in some way. Apple figured this out when they almost went the way of the Commodore by making so many damn types of Macintoshes (when Jobs wasn't at the helm). Microsoft also learned this when they had an extensive list of Windows variants (Full/Pro/Home/Home-Pro/Server/etc/etc), but I don't think they've recovered from that very well.
Now on to the meat of the problem. Linux, too many choices...what can be done? Well, as a developer, not much. It's not our job to make these decisions. We are the ones that give all the choices. Drivers for every device, apps that do anything you want, themes, icons, documentation, hardware support. The real issue at stake is some company needs to break out of the "We're a Linux distribution" mold.
Let's take Dell's Ubuntu Linux offering as an example (I'm not knocking this effort, I helped start it when I was working for Canonical, it's a great offering). If a normal user somehow gets to the Dell Linux page, and they say "wow, what is this Linux thing?", they will surely go to Google.com and start checking. Bad? Hell yes. The huge amount of information, choices and decisions becomes quickly apparent to them. They start asking questions like "Is Ubuntu the _right_ Linux for me?" and "Should I try other Linux's as well" and "Why does Dell only offer Ubuntu?".
Indeed, these are good questions, but for which there is no answer that is going to take the average user from "I've always used Windows/MacOS and know how it works" to "I'm going to try this thing called Linux."
In my opinion, as unfortunate as it may sound, in the end, some company will deliver a product that makes no mention of Linux other than in the copyright attributions and source code, and will call it something completely different. Maybe they will call it Chrome OS?