Agents and publishers like to say that no one can predict coming trends. I've always thought that wasn't quite true. I knew with no shred of doubt several years ago that epic fantasy would start to become popular again right about now. I said as much in the query letters I sent out to agents at that time, and of course they ignored me.
I told them that the Game of Thrones HBO series and the Hobbit movies would produce a new wave of interest in epic fantasy, and since most of these people would have already purchased Tolkien's books after the LOTR movies came out, they would be looking for something new. I even posted about this at Absolute Write, and several people commented there that there was no way to know whether what I said was going to be true. Hogwash! I knew it absolutely. I knew Peter Jackson wouldn't suddenly lose his deft touch at producing Tolkien properly. I knew that George R.R. Martin loved his story too much to allow it to go forward in a shoddy manner.
So it is very frustrating to see posts by respected agents now, acting surprised that this trend has suddenly arrived. Why does no one ever listen to me!