Hmm... but my discussions with people who have worked on Ruby execution engines say that Ruby's normal operations are slow (because Ruby is constrained to do many slow things for normal invocations). How does Ruby reflection compare to .NET reflection and how does Ruby invocation compare to .NET invocation?
a + b
a.send('+', b)
add ra, rb, rx
jo
Ruby really isn't constrained to do anything slow for normal method invocations - you can optimise I think literally all of them away entirely if you have a JIT. For normal method invocations this all all solved back in the early 1990s in the research on making Smalltalk fast, but wasn't fully applied to Ruby until my work (and Topaz, Ruby on PyPy achieved similar results around the same time actually). I extended it to work with reflection (metaprogramming).
Everything can be optimized at a compiler or a runtime level. Even if you just scale it back to specific idom-optimizations (as you talk about in one of your talks you've done on your JVM work) you can tremendiously boost speeds by 200 to 300% just by writing operation-specific optimizations.
It's a sad state that because of this preceived "it's going to be slow" that no one seems to be attempting to implement things that Guy Steel and McCarthy implemented way back when. This sort of lazy thinking results in the "Just right it in C" mentality that much of the python community holds.
I'm glad at least you and the JVM people are working on this as this is quite important for all CS-focust disciplines.