I bet that there is a bigger demand for PHP devs then all the Rust,Go and Elixir combined. So if you need a job you would probably have better chances knowing

I bet that there is a bigger demand for PHP devs then all the Rust,Go and Elixir combined. So if you need a job you would probably have better chances knowing PHP then knowing Rust. But if in your area is raining with Rust jobs then go ahead and learn only Rust.