It's problem with Shakespeare adaptations, too. Olivier, for example, did some of Hamlet's soliloquies as voiceover, and it's kinda weird. Branagh did all of Iago's soliloquies as Iago confessing to the camera-as-audience, and it was kinda weird, too, but less so because it was consistent. Olivier's Hamlet occasionally broke into actual speech, so it was awkward sometimes. It takes someone with vision and a good cinematographer to make something not ridiculous happen.
It also depends on how iconic the last adaptation was. I was too young (and the internet was too young, probably) when the BBC Pride and Prejudice series came out in the 90s, so I don't know if there were complaints then about possibly surpassing the 1970s series. (the 1930s film doesn't enter into it because they weirdly re-set the thing into the 1830s, and it's not like anyone in film cared about accuracy in 1930s film anyway.) I do recall that the 1995 became so iconic that when the Joe Wright version with Kiera Knightley went into production, there was plenty of talk of "and what's the point?" even though it had been ten years since the last one, and the last one wasn't even on the big screen. I don't think anyone cared so much about two Mansfield Parks in about ten years because damn, that film had issues and it wasn't like Billie Piper in the tv version was ever going to be iconic as Fanny.
There are 3 versions of Show Boat on film (one mostly silent, with the interpolation of songs from the show in a film that was really based on the novel), with the two real musicals spaced by about 15 years. But most musical films date from later (the latest Show Boat film was 1951)and tend to be considered iconic. The American TV channel ABC tried, in the 1990s, to do some for-tv remakes, some more successful than others. But it's expensive to film since so much has to be separately recorded then lip-synced in filming, and the market wasn't huge. While i'd love a better film of The Sound of Music (personal taste: the marionettes drive me up a wall, also that opening scene MAKES NO SENSE in the lyrics since it's supposed to be dusk), Julie Andrews and Christopher Plummer are iconic; I'm not sure anyone could get out from under that.
So the Phantom question is really going to be whether it kind of fades out of consciousness (maybe with a non-musical additional adaptation helping that along) or if somehow Emmy Rossum as Christine is Yul Brynner in the King and I - inappropriate casting but iconic for loads of reasons. Unfortunately, it'll be a good twenty years before we can start to figure that out.
What kind of literature and what kind of life is the same question. - Tom Stoppard