I gotta say this: The number YA graphic novels coming out each week is insane. We specialize in YA GNs and there is no way I can order them all, or even a hefty percentage of them. I'm taking a wait and see attitude toward most of them, unless they are part of a series that we're already carrying.
It's the usual thing of when something gets hot, everyone follows. I could say the same thing about coloring books, or Tarots, or Greek mythology books.
Sometimes a single book can inspire an entire genre. I'm not sure who started Romantasy (fantasy+romance) but Sarah Maas is the queen. "A Court of Thorns and Roses"is emblematic of books with two or more nouns combined. Again, total overkill.
There are diminishing returns on these types lemming books, so as an author, you need to be one of the first to jump on the bandwagon. I'm sure that authors everywhere are instantly changing their titles and descriptions of books already in the works or even finished, in order to be in the zeitgeist.
My first book was homage to Tolkien, but Sword & Sorcery was hot when I sent it off, so the publisher bought it on that basis. Close enough. I loved S & S almost as much as high fantasy.
The covers of books also give it away: if there is a hot book with a distinctive cover, it doesn't take long before you see cover after cover giving off the same vibes. My book "Star Axe" had an undeniably Frazetta-ish cover.
I mean, it's true of everything. Most of us are followers, even if we deny it. But a bookstore can ride the wave a little too long and find out not everything that is based on something hot is going to be hot.
