You are overlooking the 50%+ of people who are not mentally competent to handle a modern PC. People who haven't upgraded their Windows to SP1 because they don't

You are overlooking the 50%+ of people who are not mentally competent to handle a modern PC. People who haven't upgraded their Windows to SP1 because they don't want to mess with it, who dedicate 60% of their CPU time and screen real estate to malware, who think Skype keeps uninstalling because they haven't pinned it to the taskbar/dock and the icon vanished after they quit the app.