When people ask me why I love my job so much, I always say, "because I learn. I learn every day. It never stops."
I think of myself as a writer first, and a writer covering technology second. The technology part is important, though. There are other fields of writing where I think I would learn less, or at least at a much slower rate, than I do now.
There are other reasons I gush about my job, of course, but I think learning is inherent to writing. Anyone who is averse to new ideas, or who doesn't like being challenged, or who prefers to stick within their comfort zones will be a rather poor writer.
Even though I write about technology primarily, I don't feel like my life course as a writer is at all set on that subject. I love the notion that writers aren't expected to be experts in their subject matter, at least not at first anyway. It may come later, though.
Take Steven J. Dubner, best known for writing Freakonomics and hosting the Freakonomics podcast. His co-author, Steven Levitt, is an economics professor. Plenty of the people Dubner interviews are experts in economics and psychology. But he doesn't have a degree in economics at all. He holds an M.F.A. in writing (if I recall, it's in creative writing, although I couldn't find a source confirming it) from Columbia University.
Another example is Joshua Foer, a writer who, in researching and drafting the book Moonwalking With Einstein, studied the art of memorization to the point that he tried it himself and won the U.S.A. Memory Championship. Would he now be considered a memory expert? To some extent, absolutely. Is that the be-all, end-all for him? Not by a long shot.
Alain de Botton, another writer I deeply respect, has become a semi-expert in more areas than I know. He often writes about the philosophy of something, although that "something" changes all the time. To research one of his books about travel, for example, he lived inside Heathrow airport for a week. But he's absolutely not "just a travel writer," as is evident by his other books, such as Art as Therapy and Status Anxiety.
I think about this concept any time someone says, "If I could do college/university all over again, I'd study..." I never suffer from undergraduate-major regret. I could write about architecture, or engineering, or sociology at any time, as long as I pitched it right. For writers, it's never too late to learn something new. We get to learn and be whatever we want.