As my last thought regarding writing a story good enough for publication; it seems to me that in a world of roughly six billion people, about eight billion want to be writers.
There's a lot of manuscripts out there that should get published on the merits.
Figuring out what the market wants is a publishers job. A writer should write what they write best. Rowling could never have written a story about an angsty teen girl, and her vampire not-lover. She's a Classicist, so she wrote a story with a lot of classical elements.