Liar.
It all depends on how you design the OS. That's the whole point of standards: interoperability. Design it right, and components will be completely interchangeable, even if they are very different.
Microsoft has a point about integration of various apps with the operating system. But they have done it in an unethical manner, that is, a way which undermines (or even destroys) interoperability. The sanctions requested by the remaining nine states seek only to force Microsoft to design their system properly, that is, in a manner in which the parts are interchangeable and interoperable. This can be done, without even modifying the end-user experience. Heck; it could be done to IE with almost no modifications to it at all. WiMP might be more difficult, but still not impossible.
The guy's just trying to save a business model built on a pack of lies. And it's high time for that business model be recognized for what it is, and brought to justice for it.