I would disagree about it being elegant. It's a fine language, but it has no unifying concept. It's procedural, it has anonymous functions, it has simple OO built-in. This isn't really elegance because you can't go anywhere uncharted with this. The simplicity is there because there isn't much built-in. Code is not data. There is no module system. There is no generalized flow control. (I am not sure why language designers like manually implementing function calls / return, exceptions, loop/break/continue, etc. when continuations generalize all of this.)
Anyway, JavaScript is useful, but it is a limited subset of nearly every other language. This may be good, but where features are missing, everyone has their own incompatible "fix" for that. That may or may not be elegance; I'm not sure.
You're right.
What self respecting Startup would bother with such an obviously deficient language? It's just not up to the job. Just keep using your Turing complete C/C++, Java (or insert your own favourite Turing complete language) and everything will be alright.