Except that's not the trade off, because the slop producers would then just create more accounts instead of uploading more books on the same account. Which is probably what they're doing even with the existing rate limit.

So all you'd be doing is inconveniencing the actual human who just wants to use one account for all their books. Of which there could easily be more than one.

Moreover, trying to justify things with ratios like that proves too much, because slop can give anything a ratio like that. They can generate trillions of books, any number. If you banned everything then you'd be banning millions of pieces of slop for every one human-authored book, but you'd also be banning every human-authored book.

What you need is the thing that minimizes false positives, because the base rate of true positives is now so high that even a negligible false positive to true positive ratio would swallow most of the real books.