[twelve40]

yeah "better programmer overall" seems rather vague. The OP seems to be asking specifically "is it even worth it to stay in JS anymore", not "how do i become a well-rounded individual".

I personally prefer to hedge my bets by doing both backend and frontend work. If you join a smaller place/startup, you may end up having to push both. Saying, "I can build anything and I can help across the entire stack where needed" and showing history to back that up i think is a positive. Yes, a github project in a different stack might come in handy at an interview.

[sokoloff]

I left a few assumptions out of my response that may help anchor my advice back to the question as originally asked:

There will, for the next decade and likely the next two decades, be several million jobs that are using the Javascript ecosystem. (out of ~30M programmers worldwide). If OP (or anyone else) is happy enough working in that ecosystem and concerned only about ongoing employability, finding a way to be in the top 10% of Javascript programmers is more than sufficient. (Being in the top 25% is probably more than sufficient.)

If you start from a base case of 10K hours of JS experience, are you better off with that or instead having 9K hours of JS, 250 of a lisp, 250 of Java/C#, 250 of golang/rust, and 250 of SQL? I think the latter candidate is far more likely to be able to succeed and thrive in the JS world than someone with the "extra" 1K hours of JS experience.

I think you choose JS or not based on whether you like working in JS, then if you choose it, you find a way to maximize your chances for success, which I think is "something different from JS and happens to be 'become a well-rounded individual'."

[nassimsoftware]

This is exactly what I'm asking about. You hit the nail on the head.