But I'd argue that the most used microsoft product in the world (besides Windows) is MS Office. What holds a lot of people back from running Linux is that they don't like dealing with compatibility issues with LibreOffice and MS Office.
Microsoft knows if they open source or port MS Office to Linux, they will lose a massive market share and millions of people will stop using Windows. And I don't blame them, any reasonable business would not do something like that.
But unless they do that, I don't see how they can claim to be cooperating when they refuse to port their main product to Linux.