Thinking in terms of skillset breadth only makes sense if you see yourself as 'solving Java problems', 'solving Node problems', etc. I just see my myself as solving (ever more complex) (business) problems, most frequently with Java.
To put it another another way: programming languages are just tools. A small amount of experience with lots of tools isn't necessarily better than a lot of experience with one tool, all else being equal. This also somewhat relates to what they say about having 10 years' experience versus having 10x one year's experience.