Programming languages alone aren't the only things you have to know in order to be a professional developer. It's also important to keep up with the ecosystem around that language, and industry-wide trends in application design, testing and deployment/ops.

Good luck getting a Javascript job if all you know is jQuery, and you've never touched Webpack/React/whatever else JS devs need these days. Maybe JS is an extreme case, but some version of that same phenomenon exists for all the languages you mentioned.