I have no knowledge of this from Microsoft internally whatsoever, all i know is what is posted in this article.  But if it's true, I think it's a great idea.  Why not let anyone who wants to develop for your platform?  It's what has made Windows so successful.  There may be some concern about game quality/testing etc. but that could easily be addressed by not giving the "official stamp of approval" to games that haven't passed the required testing; everything else would still run, but they would be restricted in using Xbox logos, Live integration etc.  Anyway, just some thoughts.