not to mention
With steam now spread over mac windows and soon linux, devs may find it easier to just code their games in openGL from the get go, rather than making directX for the windows version and openGL for everything else. With any luck that may move more developers over to learning and using openGL while encouraging them to ignore DX.
Honestly I kinda wish microsoft would drop DirectX and donate some of its codebase to openGL. It'd save microsoft money in the long run, rather than spending money on a technology people don't actually buy, and give us a greater graphics API by the end of it.
Sadly we know that'll never happen.