I don't quite get this sentiment. In my experience, the career opportunities come from solving worthy problems, as opposed to using a particular language. Plus, I don't believe that an engineer should be identified by a language, as in a Go programmer, or a Java programmer.
But often, a client needs a developer for an existing stack, and advertising as a Go programmer (for example) gives you an edge over someone who doesn't, in my experience.
I don't quite get this sentiment. In my experience, the career opportunities come from solving worthy problems, as opposed to using a particular language. Plus, I don't believe that an engineer should be identified by a language, as in a Go programmer, or a Java programmer.