[Auzy]

You also forget that since the Linux kernel is GPL, its probably illegal to release closed source drivers (such as Nvidia's for Linux). I might be wrong, but we all know that the legal grey area Nvidia exploits if tested in court might not hold up. Nvidia though, despite using a closed source module is probably the main reason linux survived. Then again, what kind of sensible OS requires drivers to be recompiled to work the moment a kernel is upgraded?

Also, Microsoft goes to incredible lengths to ensure backwards compatibility (even with their competitors software), whereas any backwards compatibility in Linux seems to be coincidental.

Those are 2 reasons I use Windows 7 now. But that's just my opinion (all OS's these days have their own problems).