I disagree - JavaScript is the most used programming language in the world, and were I a betting man I'd happily wager client JS is still a much bigger share of that than server.

Yes, there have been a lot of advances in modern JS for things like atomics and other fun memory stuff, but that's just the natrual progression for a language as popular as JS. The 3 main JS engines are still developed primarily for web browsers, and web developers are the primary audience considered in ES language discussions (although I'll concede that in recent years server runtimes have been considered more and more)