I’ve seen people talk about actors and artists that had a terrible time.
My own would be Anne Rice. She wrote Interview with the Vampire after her young daughter died of Leukemia. Then her husband suddenly died of a brain hemorrhage. I suspect her Christian, anti-fanfic phase was a result of mental illness and manipulation from the publishers, although I don’t think she ever apologized.
I think it might have had more staying power if the movies based on it were better.
A big part of Lord of the Rings’ current spot in the cultural landscape has to do with the PJ trilogy. The books, in and of themselves, were always massively popular, but the movies gave them much greater reach, with all the merchandising, video games, etc. that followed.
Anyone passively familiar with Lord of the Rings will be able to tell you the plot, name a few characters, etc. I’m not sure I could say the same about Conan, except for the titular character.
Conan really didn’t have the same kind of reach overall, which is a shame.