C explicitly states what an implementation should and should not do. The same with C++, FORTRAN, and other standards. Javascript is a standard written by committee. So why can't it tell implementations what is good behavior and what isn't? Other languages do.
I think there's a distinction to be made between the language spec (e.g., interesting Javascripty details like what is the result of `"" + 1`) and integration issues like what to do when the browser window detaches, how many threads the browser will devote to running Javascript, what to do when some of those threads appear to be blocked, or how should the runtime/VM attempt to recover from deadlock or OOM.
The implementations are what matter. They're the only thing that matters. It's the business axiom "Ideas are worthless, it's the implementation that counts" at work.
Ask yourself this: If V8's performance was still at 2010 levels, would Node exist?
And if some other language were the one which had been picked for browsers - JavaScript relegated to only running on servers - I wager JavaScript would hardly be used at all.
V8 is a good runtime implementation for a pretty weak language. Personally I don't think node's existence is a net positive for the world. Ask yourself if we'd be farther ahead if the browsers of 20 years ago ran Perl instead. Anyhow, this entire thread already supports the two ideas that (1) implementation is hugely important and (2) not all issues are language issues per se.
