Human-generated slop is real.
I've read a LOT of fiction. I love reading. And if it's good enough, the idea of reading something created by a machine does not bother me at all. So of course i will continue to see if the machine is finally good enough and i can be a bit more specific.
10000s is still much smaller than the space of possibilities for even a short prompt.
You might be right that good human novels are better than what LLMs can manage today. But that's rapidly changing.
And if you really need that Harry Potter / Superman / Three Musketeers crossover fan fiction itch scratched, you might not care that some other existing novel is 'better' in some abstract sense.
Tens-of-thousands is probably low by something in the neighborhood of four orders of magnitude.