Even in the software world there is a growing expectation you are an expert in a single area.
What if you are an expert software developer, regardless of the language? When a project lands on your plate you need to ask yourself if you plan on using the language the customer/employer wants you to use or the language you'd like to use. In many cases you are going to use the language that the rest of the team can support in the long run. Still, you'd like to use a lighter, faster, shinier new language to make sure you stay current. However, development skills have become more specialized in recent years and that is actually hurting our career field.
If you've been working with OS's, databases, languages, scripting tools, build tools, etc. etc. for a long time then you may be too experienced for the current crop of companies looking for good people. By too experienced I mean you have yet to specialize your skill sets and forget everything else you've learned. You are a polyglot engineer or a language agnostic developer and if asked you can spin up and be an expert in a given language in short order, pulling from years of experiences, your expertise can shift depending on the project at hand. If this is you, you may be too experienced and finding a good fit in today's world may be more difficult.
Please, if you are a PolyGlot Engineer, Language Agnostic Developer or just a well rounded software type person, don't change.