Yeah, that's right. The Windows Services for Unix was whipped up back around 2000 so they could claim POSIX. But Microsoft never treated it seriously, it was never very useful, and they nearly deprecated it from time to time.
This time they're running scared and they know that to survive they have to attract Linux users and developers, which is a very different, and much more powerful, motivation.
Considering the overwhelming majority of mainstream business software runs on Windows PC's and Windows Server environments, I'm not so sure Microsoft is running scared.
What they ARE doing is giving developers a choice in the environment they want to develop without consideration to the underlying OS. Personally I think it's a good thing. It's going to expand capabilities beyond the individual OS platforms themselves.