Linux however, will never be the primary desktop OS in the world. It just won't happen, because you have to posess some level of masochism to want to use Linux on an everyday basis.
In lamens terms, imagine you've got two cars. One of them is brand new and for the most part, works. When it breaks down of course, you take it in for repairs, but you don't need to know anything about it to make it work. It just does.
The other one though, instead of turning the key and having it start, you have to kick over each part of the ignition process manually. Then, instead of pressing the gas and having the car move, you have to take apart the engine and tell it exactly how fast you want to be going, an aproximation of how far, and what speeds in what areas. Then, you don't just wind down a window. You have to install the window winder yourself, because it doesn't come as stock, incase someone else didn't want it. Also, forget about the radio because you just don't speak FM/AM. No tuning dials here. Now that the car is started, moving, and maybe has the window wound down, you want to turn? Oh shoot, thats a steering wheel that other drivers haven't included support for, looks like you just cant turn. Oh well ^_^
Now, given this crude example, which car would YOU rather drive?