Linux failed in the desktop market thus far, and probably will until someone comes up with an OS that is at least as user friendly as OS X and then actually has the ability to get it into users hands.
I don't, necessarily. Or, more accurately, I used to, then I didn't, and now I don't really care.
I long ago realized there's a sweet spot technology when that technology is used enough to be popular in niches, but not enough that skills in it's use and maintenance are commoditized.
Professionally, this results in more demand for your skills. Personally, this allows you to invest some portion of your identity/personality in your choice, especially if your identity is slightly nonconformist (this isn't necessarily a good thing, but it can feel good).
That's partly because the desktop became more irrelevant, while mobile became more relevant, and linux dominates the mobile market. One could say that the it switched from being about "the year of the linux desktop" to "the year of the linux palmtop", and that already happened.
Of course, depending on your point of view, that may just be double speak to obscure original point, which to varying degrees it most certainly is.