I doubt it would ever have been seen that way by serious cinema historians, and the 1997 reissue of the entire trilogy in cinemas decisively proved otherwise as far as the general public are concerned. But in 1990, I heard similar mutterings, so you've got a point. Still, Star Wars couldn't ever fit my definition of a cult film, even if it had ended with the original trilogy. See here for why: https://medium.com/cinemania/what-constitutes-a-cult-film-dfc6dd5d1a72