I started off like everyone else does, slogging but having a compulsion to put words on paper. I didn't write or read horror or fantasy, other than children's fantasy, until I was in my teens.
I try not to worry about rewriting books that worked well the first time. I'm too busy writing new books to worry about things that are already in print.
I went to Marion College for writing and I was kicked out of the writing school. I was asked to leave the writing program because I was corrupting the other students.
Nothing wrong with making money or doing what you need to do to sell, but I think it shows when you're writing something to pay the bills and when you're writing something because it's really your version of the world.
For me the Anita series is built like a mystery series, which means that as much as possible each book stands alone, so you have a mystery to solve from the beginning to the end of the book.
Readers respond to every genre intensely, if it's a genre that appeals to them. Again, who can say why anyone enjoys horror and dark fantasy? If I can't answer the question for myself, I wouldn't dream of trying to answer it for others.