It will never do it because, as they say, "Elvis has left the building." Elvis was Bill Gates. Steve Ballmer (right), on the other hand, is the strategic equivalent of Tom Jones. He has one act, he does it very well, but that's all he has. Open source is not part of that act.
Ballmer made his bones by working with re-sellers, "in the channel." He is a genius at extracting money from that channel. It is uppermost in his mind.
Any strategy that bypasses this channel would fit Ballmer about as well as one of Elvis' outfits might. Besides, you don't get anywhere in mobile without the channel, specifically the carriers. If you think Microsoft is closed talk to Verizon Wireless.
It's true that Microsoft has, over the last few years, taken a few steps down the open source incline with its shared source license. Tom Jones raps, too. But I no more think that Jones will become the new third member of RunDMC than I believe that Ballmer will break the channel and go further down the open source incline.
Unless he does something remarkable, like replace Ray Ozzie with Paul Murphy.