Scala (and Java itself) are much easier to build native compilers for than Clojure, where numerous values are actually small dictionaries, nothing has a fixed type, and a large amount of the code is expanded from macros that are expecting to executing in the environment of deployment (not some special compilation stage). It is a language that essentially needs a heavy runtime to be remotely efficient (as anything super small is going to be rather equivalent to a barebones/naive JavaScript implementation), and it is unlikely that an attempt to build out a nice runtime for it is going to somehow be extremely better than the JVM (or a JavaScript engine, which might be even better in some ways).