I have tried writing on many different subjects and occasionally done well with topics like copyright and environment. But those wins are occasional, and the majority of my articles in those topics flop badly. I kept writing them because I like diversity, but the real challenge is how to reach more people with those non-writerly stories because they don't seem to be well distributed. And this is the one and only reason why I ended up writing about Medium and writing. Because they actually got reads!
I write about Parkinson's disease and neurology, but they are among my lowest earning pieces.
It's going to be a battle to gain traction in other topic areas.