EWS is actually a great movie. Took me a few tries and getting older to understand the themes. It's there with the other Kubrick movies for sure.
The problem in my view is that EWS's failure was in that most people just didn't identify enough with the characters or their struggles other than a superficial 'affluent married couple with divorce lawyer on speed dial with illuminati'.
In fact, it's just become a favorite topic of conspiracy theorists that have largely decoupled from the story line, and in my view, simply did not do Kubrick justice since an artisan or creator's final work is always scrutinized. I remember large parts of the movie being edited out which allegedly enraged Kubrick and put him at odds with producers.