Just adding that JavaScript is also the best at something - running code sandboxed - especially in a web browser. Like SQL for databases, JS has no competition for web development (because the web needs full compatibility, and adding another language doesn't have a good value proposition - just compile to JS) and thus is immensely popular.

Most languages have something they are the best at. SQL is probably THE language with the strongest value proposition - relational databases are even more important and ubiquitous than web browsers. But why doesn't SQL have any competition?

I would love to see an alternative to SQL in the style Jamie suggests. Maybe SQL would immediately not be the best anymore?