Because that's the best existing engine (even with Zilla nicely catching up), with dozen of genius and millions of dollars dedicated to it since the beginning a

Because that's the best existing engine (even with Zilla nicely catching up), with dozen of genius and millions of dollars dedicated to it since the beginning and for the next years to come. Why do you think JS became so much faster compared to the anemic octopus is was before ? And can you imagine the perf of Ruby or Python if a 10th of those resources were allocated to those ?