Agents warn authors all the time not to chase trends, and I don't think most people doo. I think it's more an issue of the idea coming too late to catch the wave. Take one of my current WiPs. I'd had the first seeds of this idea germinating for over a decade (yes, it was a slow-starter) before the plot and characters finally came together. Once it did, I wrote the entire manuscript in a month.
The only problem is that it's a genre that already had its trend time. (Like... right now. The saying that the when the books start coming out, it's too late for your manuscript? Yeah. That.) However, there are a lot of people who are still interested in the story. I just had to do something to make it stand out.
So... I took a good, hard look at the manuscript and said "What if?" (again--since that's how most stories start). Now, I didn't want to mess with the heart of the story because it still spoke to me. And... I loved the characters. But what I could change was the world-building, and the more I looked at it, the more I loved the idea of the changes.
As soon as they were settled in my brain, I dove into the revisions. One of the ways I know something really works for me is how quickly and easily it comes together. Even more than the original version, this story--with its new societies--works for me.
So how did I work around the "trend" issue? I mashed genres. This manuscript is the first in a trilogy, and conveniently enough, there are three very different societies in the world. Each of the installments will focus mainly on one of the three until all are covered, and I can't wait to start on the next one. I hope beyond hope to share these stories with you because I think it's a tale worth telling... and hopefully worth reading :)