don't stone me just yet... but i kind of agree with those slides; well most of them.
i used linux before, but jumping from windows xp to 7 was a breeze and super fun. anybody can go in there and tweak it for performance, or visual effects and stuff.
linux has always been a freaking mystery.
there are hundreds of distributions and even different versions have differences that you might have to relearn, it's a real pain to use linux.
i don't know about mp3 players or any peripherials or software, but gaming? yeah right! good luck first finding a video driver that works.
for the average consumer, linux might be a bit too much trouble, so yeah, buy windows.