Why doesn't Linux have a larger share of the OS market?

Linux actually has the largest share of the web server market, so you're probably not wondering about it's popularity in that regard.

Many people point to different issues with desktop Linux, and think that once this barrier is overcome, it will become the "year of the Linux desktop." However, it is likely a combination of these factors that slow the growth of Linux in this area.

The first reason is that in order to take a significant market share, you have to market. When was the last time you saw a commercial on TV, telling you to get a computer with Ubuntu on it, instead of a Mac or a PC with Windows? If no one hears about it, they aren't going to be interested in trying it.

The second reason is the (perceived) complexity that people like to portray Linux as having. Not to be cruel, but a large number of internet users one will come across will communicate on a third-grade level. They don't understand relatively simple computer terms like "partitioning", "formatting", or "open-source." They want to know why they can't play RuneScape out of the box, or play MP3 files, or DVDs.

The third reason is probably the fact that they first have to deal with an operating system already being dominant. Many manufacturers don't provide any sort of drivers for Linux, or supply specifications so that others can write them. Many software companies that make popular products don't make a Linux version. Many computer retailers are locked into licensing agreements with Microsoft, so that they effectively can't sell a computer without bundling the cost of Windows with it. Not many people are going to be interested in Linux if it costs them exactly the same as Windows, but can't run half of its programs.