@givemersspls funny side joke with this in the LN is that all the series he says his book is better than aren't just random LNs. For every one of them, the authors read volume 1 of imosae and wrote an afterword for it, which ended up in the final volume. He's throwing shade back at their series as a joke.
Mind you shit like arifureta still managed to happen in the modern age. In that case apparently it was everyone's fault because the original adaption attempt was shit so they replaced half the crew... that still mange a shit adaption and the author wasn't happy. The first adaption attempt could've been slightly better but apparently it didn't follow the plot and the second one followed it while skipping over a lot of the key details that made arifureta appealing. Arifureta was one of the top selling series in japan but the anime scored pretty horribly.
This is when I saw the t.v. version of this series that it instantly was better than I expected. The rich number of secondary characters that all feel like the protagonist of their own stories that have their own life outside of the primary character and the existence of opposite-sex characters to the primary character that don't automatically become part of his harem but have their own love life.