I don't think it's surprising at all. As mentioned here, people are looking for alternatives to spending time online all the time. Then, as the article mentions

I don't think it's surprising at all. As mentioned here, people are looking for alternatives to spending time online all the time. Then, as the article mentions, LOTR, GOT, and Harry Potter have primed the culture to be big into fantasy. And finally, we're a good 30 years past the peak of the D&D bashing by religious types and the stereotype of it being a game for basement dwelling stoners and creeps, which means we have a full generation of young adults who don't have huge preconceived notions about the game.