Remember back when Vampires were all the rage and we got all kinds of moviea and TV shows featuring Vampires as characters in the 1980s and 90's, then that spawned into over 'sexy supernatural' creatures including Witches, Werewolves, Angels and Monster Hunters until culminating in the sparkly vampires of Twilight and the Winchesters last spluttering breaths.
Now we get the rise of the Superhero genre, which Marvel has been able sustain by going multimedia and pandering to audience demand, DC has finally been able to pick up the baton as has Netflix and others creating their own response to the genre. Like the Vampire era I predict another 10 or so years for Superhero dominance, then a slow decline for another 20 as the genre runs itself out and another one rises to take its place. Of course we did have a Superhero blip in the 70s too, so its likely to come back again.
The big question is since we've had Vampires and Superheroes and Sci-Fi and a few attempts at Fantasy in the past few decades, what will be the next genre to dominate...