With GraalVM around, niche languages can pretty much take advantage of the significant investment into the JVM. Its whitepaper is truly novel, but the gist of it is that one has to implement an AST-based interpreter for a dynamic language, and then it will make use of state-of-the art JVM GCs, JIT, etc. TruffleRuby is the fastest Ruby implementation around, GraalJS can after warmup match the performance of V8, so it is indeed a very interesting technology.