What would happen if the windows OS source code was released to the public? Nothing. People would fix a few bugs if they could nail them down, but it must be millions upon millions of lines long. How much good would that do anyone in the next few years? Trying to document and tame that much source would simply be evil.

As far as the licencing is concerned, I think it's everything included. I hear MIT has it, and they work on parts of it to clean things up. The original Kerberos came out of some such agreement, I read somewhere. The NDA underneath it I hear is also quite killer.