What would you base that assessment on? If that were true why would lInux, which had exactly the same combination of possible buyers (techies plus people seeking really budget computers) not have beaten Windows long ago?
* flamebait mode on *
Because Linux STILL F* SUCKS! Even tried to use linux for anything desktop remotelly serious? Office suites on it are still a joke (I am lookin' at you Open/LibreOffice), it is still hard to do anything gui-wise, some stuff still lacks any useful gui, while some other don't even had any. Try to configure sound for example. Or try to use any intel graphic card (majority of OEM PC's come with them). I use linux daily, have used from many distros, used gnome, kde, E15, E16, E17, XFCE, black box, you name it, but to say it is as usable as windows or OS X, that's a dream, and most tech users agree with it (even if they don't speak so, but OS usage figures speak wonders for that)