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.
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.