One of the problems of owning 90% of the desktop PC market is that the productivity of the world's desktops can be attributable to one company: Microsoft. It's not possible to hide behind anonymous statistics when everyone is using your software.
A recent issue of Inforworld concluded that over 50% of users are not engaged or actively disengaged at work due to the distractions of Internet access; an IN Education Technology Commission report concludes that over 50% of teachers complain their PCs aren't reliable and tech support is hard to get. PCs stopped adding to productivity a long time ago. Today they are primarily entertainment appliances.
Can we blame Microsoft for building systems that invite abuse, waste, mischief and maintenance headaches? Yes.