Readers read almost everything they see and after a while, they notice patterns.
They’ll see a generic love story with about the same plot. The same strong female must pick between two male lovers. Or the same werewolf characters. Stories start with someone waking up. The same Christmas tales over and over. Or stories about characters that want to become writers.
After a while, readers don’t want to read the same plots. Some publishers refuse to read those plots because they know they can’t sell those stories.
But recently I’ve found an interest in stories that mix generic stories up. I’ve read a few books before, such as Spelled or Sisters Red, that poke fun at those generic stories and end up creating something new by the end of it.
So, perhaps instead of writing the same types of stories because someone else is successful with it, writers should create interesting twists that make their story stand out among the rest. They can define their own fairytale without the help of the Brothers Grimm.