Because Linux is just a "niche" thing, a curiosity. Serious things needs either Windows if you are a spreadsheet/powerpoint kind of person, or Apple stuff for design/publishing, etc, because it's "much better" for that. Oh, let's not forget that Apple stuff today is built over UNIX, so it's "rock solid", while windows 7 also uses "NT technology" (do people still know what that is? ). Linux also has UNIX technology, of course, but it's not built by hired pros, you know. What are your guarantees? With Windows, your satisfaction is guaranteed! Plus, it costs less, there are studies that show it. And there is of course the learning curve thing... For big companies Linux is just a political stick to show during negotiations with Microsoft. And is also the system that idealistic geeks will waste their times porting themselves to each new machine so they can finally start using them for their work, X months after everybody else.