In my talks and workshops, I'm often asked whether it's a good idea to try to capitalize on current trends in novels or screenplays. The answer is no, and the reason is encapsulated in this quote from Humphrey Neill, author of The Art of Contrary Thinking:
"The crowd is right in the trend, but wrong at both ends."
At the start, the crowd would probably say, "Wizards? Kids today aren't interested in reading about wizards!"
At the end, they'd say, "Yeah, wizards are where it's at--the more the better!"
See, wrong at both ends. And in both publishing and film production, the development and lead times mean that it's very hard to come into a trend in the middle, when there is profit to be made from some "me, too" products. Usually the people who do come in at that phase either happen to have already written something in tune with the trend and get it into the marketplace super-fast, or they are commissioned to crank out something by a publisher or studio ready to move fast.
The best advice still is to write what you believe in...who knows, you might just create something that is the start of a new trend!