So, while this article says that demand is high for "Developers who are expert users of Microsoft's software programming language .NET...". You should focus on the key-word here, "expert". I think what they are infering here are people who know the ins-and-outs of the framework and the language, the software engineering process.
We have high demand for "expert" .Net developers. But the pool is so limited. Most candidates we interview come from non-enterprise groups. Their knowledge of the framework (or any framework) is limited. And they lack sound software engineering experience.
We do find plenty of Java developers with enterprise experience and from rich software engineering experience. We've hired Java developers for .Net positions, and in all cases they have transitioned well and exceeded expectations.
So, for my company at least, we have high demand for "expert" .Net developers which is being met by java developers.
My company's experience might be unique considering we are in NYC, and many of the Java folks we interview are from large financials.