Here’s a (probably pretty spot-on) piece on why the average computer user has no interest in Linux (assuming the average computer user even knows what Linux is). In summary:

1. People don’t mind Windows as much as Linux users think they do.
2. There are too many types of Linux to choose from.
3. Hardware and software compatibility is a big deal to most people.
4. The command line is not a superior alternative to graphic user interfaces for most people.
5. And finally, to quote directly: “Linux is still too geeky.”

I think that last item pretty much sums up the previous four, though. Some die-hard Linux users seem totally baffled that the average computer user would choose the OS equivalent of a clunky station wagon over a free, rocket-powered tank (to borrow Neal Stephenson’s metaphor). The truth is, though, that you need to be interested enough in computers—no, not just interested, but dedicated to a certain kind of computing experience—to choose Linux over one of the “default” alternatives. Most people don’t want to know how their computers work—they just want them to work. Most people don’t want to take the time to learn and customize.

Once you get used to a new OS, using it doesn’t really have to be a hobby. Learning to use a new thing that doesn’t hide the complicated parts so much, without phone tech support, would essentially require taking on a new hobby for the average computer user.

I will say this, though: when the Open Source community starts attracting (and deferring to) talented designers in matters of user interface, I may be willing to take all that back.