The only thing that could cause such a "ditch and switch" would be Oracle screwing up - which let's face it is quite possible with the way things are going for them. But in any case, I never alluded to that. I simply said enterprise apps that might traditionally have been "built" with JVM will in the future be built on .NET CLR. I stand by it. The JVM is ancient and it seems they are scared to improve it because nobody at Oracle dares touch it these days. Just look at their attempt at lambdas (aka. delegates in .NET as I'm sure you know). And it still doesn't have value types. Anyway, this is highly tangential now.
They don't have any reason to switch to GNU/Linux VM instances instead of Windows ones, the infrastructure costs are a tiny portion of the overall project costs.