Should writers stick to one genre?

I could not agree more. And I am like you in the sense if a story starts to turn over in my brain then it is what it is. That is why when you re read your stories, you know if there was a “right” way and then there is a way someone else wants you change it. I don’t mean editing, I mean, as in, for instance, the person who actually sent J.K. Rowling a letter telling her how she needed to change her Harry Potter series to make it better. I would not do that if my life depended on it. She said she did not answer it, and no matter what you think of HP, I would have written the “fan” a reply that said,
“Who is the billionaire?”