I once went to a talk by Charlaine Harris. It was back in Australia and it was held in a cinema. I almost missed it, if it wasn’t for my friend Will being a member at this book store chain (can’t remember which one). There was an email for members, inviting them to listen to her. I think it ended up being sold out actually. Anyway one of the things she mentioned was that when she first published her Sookie Stackhouse series, there was no other books like hers on the market. She was the first of that genre. Then as time went on other works from different people were added. Charlaine didn’t let the fact that her books didn’t fit into a genre back then stop her. She went full steam ahead and created an entire series of them.
The point is that as a writer, do not write for the current trends of the market. If you do you could finish your book just as the hype is over and then what. You’ve spent all this time on a book that is no longer in demand. Instead write what you love and want to read. Writers get to decide what the public wants because often the public do not know what they like until they are offered something different.