The simple point is that if Microsoft welcomed and truly encouraged competition by opening themselves, and all of their intellectual property up they'd be 10% of what they are now within 2 years. To do so would be recklessly irresponsible to their shareholders. The same could probably be said of 90% of large corporations.
Of course they're going to buy up competitors and their technology, just like CA, IBM, Oracle, etc do. It's not as if most of the little companies didn't have a mission statement of "Challenge Microsoft and get bought out by them in 3 years time" anyway. They're started by people in the hope that this will happen and they can retire in 3 years.
Standards have nothing to do with it. Market dominance is all that matters. Until MS lose this they can continue to write themselves a nice big healthy cheque ($16bn in income after tax last year) and given that the "Linux is coming" story has been running for over 10 years now they're not particularly worried (although they're good at putting on a very stern face and throwing a few chairs about for show).