Hang on a second. Microsoft is a proprietary software vendor and will attack anything that jeopardizes their revenue stream. They're putting the "free candy" sign on the outside of their van based on a business decision, not because they want to create some warm and fuzzy community effort (i.e. actually give out free candy!).
It's in their DNA to only promote things that will further generating revenue because their shareholders require it (and rightfully so, they are the owners).
Point being, they must have opened up that other stuff because some competitive threat existed, or there was a sound basis that it would create further lock-in and recurring revenue down the road. It doesn't follow that future software releases like this must be opened just because they opened other pieces of their software portfolio.