In the last few decades there's been this remarkable shift that seems scarcely commented upon. The mainstreaming of nerddom due to the rise of the Internet has brought with mainstreaming of fictional universes.
At first there were revivals like Star Trek TNG, and the Star Wars prequel trilogy. Then the superhero movies really took off in a big way. "Fandom" became a thing, to the point where you can't use Tumblr without being inundated with Doctor Who and Harry Potter posts. Now we're getting to the point where reboots, remakes and revivals seem to dominate all forms of narrative media.
Collective consciousness has become saturated by the minutiae of imagined realities, and I have to conclude that this is at the expense of concern for reality. This is not to say that fictional works can't be socially engaged. Margaret Atwood, Octavia Butler and Philip K. Dick are but a few speculative fiction writers whose work tells us more about our own world than non-existent ones. But most of our hypermediated narratives are just attention-grabbing spectacles with little substance behind them. I see this current obsession with "AU" as the cultural manifestation of the terminal state of our society. While the world is burning around us, we sit enraptured in our air-conditioned apartments consuming electricity and someone else's fantasies.
The new season of The Walking Dead has just premiered. A group of my friends are continuing to watch it, though they admit they it long ago ceased to give them much enjoyment. We've reached the point where franchise fiction can produce both literal and metaphorical zombies.