Actually the JVM support for dynamic languages (invokedynamic) was only added after .NET, thanks to IronPython project, created the DLR first as a side project, then eventually released it as part of .NET 4.0.
I imagine only those of us that work regularly with both platforms get it right, when each got what, and even then it is easy to lose track.
I also think it's wrong to imply IronPython and IronRuby failed for purely performance reasons.