The only two ways I see Linux having a chance without the help (meaning complete incompetence on their parts) of Apple of Microsoft is through supplanting or complimenting either in school usage. MS/Windows grew I'd wager more rapidly due to the saturation of the school computer than it could have without it and Apple has grown in proportion to the level of educational installment it has made whether through the rich kids buying laptops and perpetrating an envy complex or what not. Familiarity/complacency is the easiest way to make a customer.
The second way is through more people selling hardware with Linux preinstalled. But that is still a massive problem as many places charge a very steep price for outdated hardware or they list in bold that they don't offer support for the Linux installs; all while not being in the mainstream consumers line of sight and therefore not garnering any interest. Then you have the problem of what happens when the big corporations involved in making/distributing hardware modify it and lock it down under their control (this is extremely prevalent with Android). Hardware makers are their own worse enemies in my opinion. Intel let the netbook die not just because of the bickering with distributors/netbook makers over profits sharing/pricing(which is currently an issue or was one involving "ultrabooks" as well); but because they choose an OS that really isn't suited for the hardware. The sad thing is they kind of understood that and created a distro that came to be called MeeGo but never attempted to spread that around. The final nail probably is the use of locked down and almost openly hostile hardware (PowerVR GPUs).
TL:DR version: Either get to the consumer when they're "open" (IE young children in school) or get making hardware (IE your own CPU/GPU).
A final thought: There is one other "problem" with Linux. In certain regards it's magnitudes easier to use even for the "know-nothing" computer users than windows but in others...it's an utter nightmare. This to me stems from what I've always seen as a one sided view of KISS (IE the dev/programmer view). If someone can find the right balance between an end user's and creators view of KISS then they'd solve a pretty big problem which would cut down on the need for "support".
Linux in general or a specific distro must conquer an aspect of life, of the "must have".
windows did it by allowing you to install it on pretty much any pc hardware you wanted and when that wasn't enough, they cornered the gaming market, which to some is a "must have".
apple, originally they challenged the way things were. Hence the name "apple" as in "eve ate the apple" (not sure if that story is a 100% correct how they chose that name, as i did read it in a blog after steve job's death, but it made sense so thats my story). when that wasn't working for them any longer, they came out for the multimedia enthusiast, and now it seems they are catering to "simplicity" of "just want it to work".
One would think linux just being free, would be enough to put it in the place of "must have", but unfortunately most people are weary of free things, I blame devious greeks and a wooden horse for that. Linux has found its niche tho like apple and MS did, but unfortunately that is not on the desktop, its on the server. Some could even argue its found a place in the mobile market with android, but that might be just me splitting hairs not considering android a linux distro, linux kernel yes, distro...maybe when android x86 comes out as an official port.