That is not a sign of the quality of the language though. It is more a sign of how much money went into making a poor quality language perform well. Compare the speed of JS JIT VMs to Lua JIT VMs considering the investment respectively for example.
I currently do JS for a living, and I don't hate it, but most of the reasons to DO javascript coding have nothing to do with quality of language and instead have to do with how unlikely a viable competitor is to come about anytime soon.
So why M$ and Google cannot beat poor javascript?
Some things can't be solved by throwing money at them.
Lua is better optimized because it is smaller. It's been the right decision to keep Lua small given where it specializes. Given where JavaScript specializes it's been the right decision to not keep it small but to evolve it. JavaScript is big because it can be big; it has the resources to make it so.
You're wrong.
I think this is fundamentally wrong. I think you're confusing the language itself with how the language has been implemented.
Speed is entirely separate from the language. It's possible to write two different JS interpreters: one very fast and one very slow, both of which meet the language standard set by ECMA.
These days JS generally gets JIT compiled and a tremendous amount of work has gone into improving the popular compilers. Lots of tricks are involved. These tricks are quite clever (though sometimes inelegant) and result in significant speedups. But they have nothing to do with the language itself.
If so, you're basically agreeing with parent, in parent's disagreement with this from further upthread:
JS semantics are garbage... for optimizations
Of course the semantics of a language can impact how easy/hard it is to write a fast implementation for that language. And as far as I know, there isn't anything special about the ECMA specification that makes it any harder to speed up compared to other languages in the same space (dynamic languages, whose specifications were written with an interpreter approach in mind).
Still, in my mind, speeding up any sufficiently dynamic languages with eval and metaprogramming without straying at all from the language spec is like "fitting a square peg inside a round hole." And I think that has been done successfully with JS, at the cost of making it harder to reason about how the compiler is going to treat my code.