For multilingual programmers, assume your day job only let you program in 1-2 languages, how do you keep your skills up to date for all the languages you are able to program professionally?
I'll tell you why to keep being a polyglot: to have a choice of tools for
solving problems and to have a perspective.
I routinely write tools in half a dozen languages and pretty much always I'm
glad that I could choose one or another, because it fits the problem at hand
much better than anything else.
And the perspective is about knowing different approaches to a problem.
Sometimes I transfer the good ideas from one language/runtime/framework to
another, where it makes sense, but is not a common practice. And I can easily
use a language I haven't had much experience before, just because it's the
same paradigm as I already know from several other languages (I did this a few
times already).
And no, I'm not a generalist. I'm quite specialized in my work. I write tools
for OS administration.
It's not about top-down disallow, it's just restrictive for many reasons. To use a programming language to build a system within a company, I need not only the approval of my boss but also other developers in my team to know that language or at least eager to learn, that's not always possible.
Why not specialize in one or two languages... become a leader and specialist and not a generalist.