"The costs of switching from established languages will continue to be high" - this is why the recent set of new JVM and CLR languages are so wonderful. If I'm experienced with one CLR-based language, I can experiment with another one without leaving behind my nice familiar libraries and tools.

I started learning F# and Haskell around the same time, and although I still prefer Haskell from a pure language point of view, I'm far more productive on F#.