Libraries are add-ons and most can be ported and rewritten in your favorite language with more natural idioms. SWIG is nowadays the equalizer; it makes the entire C world callable from your favorite pet language. Stuff like LLVM will take you even further, once you know what you're really doing. In the mean time, use foreign functions and web service to bridge the gap where it exists.
My advice to Clojure programmers is to learn Lisp and mine its rich heritage for beautiful designs. A few months spent on a full CMUCL installation will make you a much better programmer for the rest of your lives: I was a Win32/COM guy writing GUIs for a living. When I discovered CMUCL I saw stuff I couldn't imagine. I was able to put buttons in the Unix shell and attach callbacks to all underlined text in an editor buffer. Stuff like that prepared me for DOM scripting with jquery. Look at Smalltalk and SML too.
A personal note to Clojure web framework guys, specially people using Compojure: take a look at Hunchentoot and copy all its good parts. I develop on Hunchentoot and everyday I discover an engineering decision made by its author that just humbles me. Good code makes you respect its author.