Magnitus: Most users are just ignorant about it at this point in time.
Really, the main thing going for Windows at this point is what I like to call the "high school" factor. Most people grew up on Windows machines and are reluctant to steer away from what they are familiar with.
I find it such a shame that people treat Linux as some kind of weird Alien that invaded planet Earth with an incomprehensible language. If Linux was as popular as Mac or Windows, maybe we would start seeing more AA games getting native compatibility with it, such as the new Wolfstein that is in development or the new Doom.
I´ve been using linux for almost 10 years. And all I can say that if it wasnt for the lack of compatibility with the newest games I would´ve completely stopped using Windows a long time ago. For me everything is better on Linux, less bugs, less compatibility issues and way more security than Windows.
I currently run a machine dual booting both system Windows 10 and Linux Deepin OS, since I love to play the latest games, and they usually dont get Linux support.
However I can confirm that I can run on linux all old games that GOG sells here, through Wine. I think a much better solution for the hard headed tightwads "purists" here that refuse to drop XP and upgrade their system to one of the latest Windows, would be to install one of the Linux Distributions such as Deepin OS, Linux Mint or Ubuntu. I bet if they learned how to properly use it they would never want to go back to Windows again, unless they want to play one of the latest AA games that get released every year.
Edit: Fixed some grammar/spelling mistakes