If you don't know, Richard Feynman did all of the things above. And you should go read his biographies immediately, because they are endlessly entertaining. There are a lot of lessons you can learn from his life, and one of those lessons is that you don't have to do just one thing, even if you are a world-renowned expert in your field.
Personally, I have a hard time specializing. I like to know a little bit about a lot of things. There is a phrase, "Jack of all trades and master of none," which I believe is intended to be derogatory. While I have nothing against specialists, and will often want a specialist to do specialized work, that doesn't mean the generalist is inferior.
We live in a big and complex world and, more than any time before, we can see and interact with those complexities. If you can know enough about two subjects to understand how those two subjects might work together, you can get specialists from both of those subjects to do new things that neither apart would have thought to do alone. Or, if you can't find those specialists, you could do it yourself. Maybe not with the skill of either expert, but in a way that either expert wouldn't have thought to do.
Add on skills and knowledge from different domains, and the possibilities for combinations increase exponentially. Whole industries used to be a collection of different skills that, eventually, worked really well together and became their own thing. Video games, for example: writing, animation, programming, music. It's kind of like movies, and kind of like software, and kind of like a lot of things, but when it first started a few decades ago, nobody knew what it was or how it was going to grow. Eventually, those people who could merge multiple fields turned it into its own thing. But without someone who was willing to do something outside of an area of expertise, it never would have happened.
What's great about the new world are all of the opportunities for people to bring their unique visions and collections of skills together. The more you can do, the more you can be you, and the more you can be awesome.