The massive market share that Windows already has and the fact that Windows is far more user-friendly and intuitive than Linux is enough for businesses (which are a massive chunk of the market) to stay away from Linux and use a fully supported, reliable, practical operating system. Most laymen users don't want to have to go through the terminal and use various commands just to install a simple program when they can just double-click an installation executable and be done with it. Most people don't want the problems I had with Linux either (having to install a driver just to stop my monitor from displaying fuzzy lines, having to scour the internet for a driver for my wireless, etc.). The only area that I see Linux completely dominating in the future is the server market.
