According to this article from Richard Grimes, it appears that .NET has not gained as much traction inside Microsoft as anticipated:
http://www.grimes.demon.co.uk/dotnet/vistaAndDotnet.htm
“My conclusion is that Microsoft has lost its confidence in .NET. They implement very little of their own code using .NET. The framework is provided as part of the operating system, but this is so that code written by third party developers can run on Vista without the large download of the framework. Supplying the .NET runtime for third party developers in this way is similar to Microsoft supplying msvbvm60.dll as part of XP.”
I think his conclusion is a bit overreaching, but this isn’t a big deal to me either way, and I’m neither a raving Microsoft fan nor a rabid Microsoft detractor.
However, this is good news in at least one important way:
To the extent Windows itself is not built on .NET, that in a sense leaves more room for other, non-.NET runtime environments to flourish as first class citizens, leaving more room for Java (we ship a commercial Java application, so that’s good…) and also for other currently and upcoming dynamic language runtime environments.