Agreed that people outside of .NET embrace open source more easily, but disagree that they don't embrace leading edge technologies. As an example, when LINQ was released, it was widely taken up.
Where I'm disagreeing with you was in your statement "the .NET ecosystem and culture is notoriously corporate, and not very innovative or leading edge". It may well be a framework loved by corporations ("notorious" is an emotive term with no substance), but you haven't proven to me that they don't innovate or that the ecosystem or culture is not leading edge. I appreciate you've committed to .NET projects, which is awesome, but argument through authority isn't really anything to disprove what I've said!
Sorry if you feel that I've ignored your points, but I raised LINQ as just one example, you dismissed Microsoft's embracement of dynamic languages in the framework and WPF and WCF aren't innovative apparently. Like I say, we can agree to disagree!
Edit: I've reread the thread, and I can see the bone of contention. My fault here: I talked merely about the leading edge technologies, whereas I was objecting more to the assertion that there was little or a minority of innovation. Of course, I didn't actually state that so the discussion went on a bit of a tangent. Sorry about that!
While the .NET open source eco-system is arguably decent, you've completely ignored two implied, but obvious points. The open source eco-systems outside of .NET are much, much stronger and people outside of .NET embrace open source, and leading edge far more easily.
That's really the whole argument and you've said nothing to contradict it, but feel free to ignore it. As a former contributor to Nancy and one of the rare .NET devs who's contributed a patch or two to almost every .NET project on Github I've used, I feel pretty comfortable making these observations.