I'm a huge fan of Miguel and the rest of the Xamarin crew, and I'd love to see a universal implementation of the CLR take dominance. I think maybe 5 years ago the CLR had a real chance to win in the battle of multi-language runtimes, but at this point I think the war is going to the JVM. (Chalk that up to yet another short-sighted decision by Microsoft.)
The problem is that Java (the language) completely dominates the JVM landscape still. I don't see Oracle in the game at all as far as contributing/endorsing something else, and obviously Sun was completely oblivious to anything else until it was too late in the game for them.
If you look at the CLR, VB.NET has and F# actually have significant percentages of uptake because they're actually supported by Microsoft. Scala, Clojure, etc.... are just miniscule blips on the radar in comparison.