> That phenomen[on] isn't a coincidence, a large percentage of readers in this genre will have KU because almost the entire genre they love is on there.
Note that this is, by definition, restricted to genres of the form "books so terrible that no one, not even the fan base, will pay for them".
I'm not sure that's a fair characterization. Most of the readers in these genres read a lot of books, so for them it makes sense to go with an unlimited subscription. I'm sure they may have only bought and read half if the subscription wasn't an option, but they will still have paid a lot of money to satisfy their hobbies.
Note that this is, by definition, restricted to genres of the form "books so terrible that no one, not even the fan base, will pay for them".