Desktop Linux _is_ the best system around. It's not about quality. People don't care about technical excellence, they care about _doing things_. And for now, Windows offers the easiest way of doing things, because everything works on it because a manufacturer will never release something that doesn't work on the general swath of Windows computers.

Pretty much the entire appeal of Mac is a) no viruses/spyware (because nobody writes viruses or spyware for Mac because its userbase is too insignificant to target) and b) big icons and prettier colors, making it "easier" to use.

Windows is an institution. It doesn't just give way once something becomes objectively superior; many systems have been superior to the their Microsoft contemporary and Windows didn't magically crumble. It's about installed base.