Picking up languages is quite easy, you just have to learn it. Turns out nowadays I mostly work with SQL (it’s on the required list too, I just forgot about it) and C#. Learning new paradigms is harder, but there aren’t that many of those.

I’m now wondering why even my relatively young co-workers all seemed to specialize so hard straight out of school

That’s imposed by the job market, not natural thing to exist. In fact, it’s very much unnatural.