> a new library that does the same things

Most languages already have HTTP client libraries. (In particular, Rust has Hyper. Ruby/Python/Node/Go have HTTP clients built-in in the stdlib, Haskell has http-client, etc.) Who uses libcurl really? (Spoiler alert… PHP.)

Of course libcurl does FTP and Gopher and all the things, but these aren't commonly required, most applications just need HTTPS.