Actually I think many governments are fearful of MS products because they might have back-doors built into them. The more paranoid the government (Chavez is a good example) the more they want open source where they can look at the code an know what it's up to.
once bill gates can convince chavez that he is more interested in making money in venezuela than helping GWB spy on venezuelan government agencies, and can show how the tracking software can help chavez control things, then chavez will select M$ at least for the venezuelan home user.
in a police state, the last thing the government would want is for dissidents to run spyware-free linux...
Which is why Microsoft now allows many governments to inspect their source code through their "shared source" program, as a response to open source. I don't agree with them doing it, but it's no longer an excuse you can use in defense of the Chicoms.