If Microsoft Went Open Source

From an Anonymous Reader: "The BBC's Bill Thompson has written a speculative article about the possibility of Microsoft attempting to secure their place in the future of operating systems by creating an open operating system. From the article: 'They allocate a billion dollars worth of programmers to shine and polish [The new OS] for a year, improving its compatibility with Windows Server technologies, donating parts of the Windows and Office code bases under the GPL and turning it into the world's best operating system.' Could this ever happen?