SPAMMMERS! Any decent related post would have sh-canned this long time ago.
CANonocal is making gallant strides in recent years...nobody knows what Linux is or it would have taken off long ago.
Do you see REDHAT/Fedora on store shelves? No. Y? The store doesnt want to do tech support for 'non-M$' OSes. They dont want to work for free and want to charge you 50/hr to fix your PC. They want Certifications and corporations backing them.(despite Linux has an OS certification,LINUX+ and is recongnized for it by COMPTIA, which does not need to be recycled every 6 mos, like M$ exams..)
Now the user is thrown into the C/C++/Python world and expects GAMES, and DVD/multimedia support. For a tablet PC, this would be a fine switch. Unity needs to checnge for lap/desktops, though. I cant stand it. And its eye candy-slow.
Maybe we should all go back to days of ICEWM/XFCE... Linux was created to run on scratch HW...take the ARDU-BUNTU tester as an example...I wouldnt boot a 'PC' in 8 hrs...but goes to show you...it IS possible.