Virtually all your arguments are based on the premise that because no major player supports/preinstalls Linux it isn't a serious OS. Will your tune change if HP or Dell makes Linux preinstalled and widely available?
No, I don't see the point in supporting a foreign clone of Unix when superior American originals like Sun Solaris and Apple OSX are readily available. Especially not a clone that's endorsed by every communist nation on earth, if not marketed by them including the infamous Chinese "Red Flag" version. I realize most people don't care about that, all they care about is did they get their copy for free or nearly free, but some of us have a higher grade of concerns.