Secure Audio Pathway: A closed Windows API

If Microsoft is truly committed to open standards, why aren't they making the Secure Audio Pathway API available to producers of other media players? Upon this question hinges several outcomes: Whether Windows will be seen as a truly open platform or not; whether Real Networks can prevail in its antitrust suit against Microsoft; and whether Microsoft is really trying to move from a standards-based paradigm to one where "trusted computing" trumps standards, where the only standards permitted are those at the end of a mandatory license agreement, or (apparently, in this case) not available to competitors at all.