I don't fully understand the question, to be honest, but would a purpose-built language like ActionScript qualify? It served only one purpose, and (debatably - AS3 was alright) served it well.

Otherwise, every general purpose language attempts to serve all its uses at once, which means they rarely specialize heavily into one particular domain. For example, while Rust's stdlib devs could build a HTTP library, many Rust users don't need one, good community-maintained libraries exist, and the stdlib devs don't want to sacrifice stability with something that requires as much churn as a HTTP library needs. It serves their goal of stability really well, but requires extra steps from users who need that.