I don’t know if perfect soundtracks would save your examples; I’d argue that the malaise infects everything: you can’t make a great soundtrack for a mediocre movie.
> you can’t make a great soundtrack for a mediocre movie.
I'm having trouble coming up with an example, but my dad told me that "Warsaw Concerto" was composed for the movie "Dangerous Moonlight". The movie was bad, but was popular because people really liked "Warsaw Concerto".
Xanadu was a terrible movie, but the soundtrack was a critical and commercial success -- it went to number one in 11 countries, was certified double platinum in the US and had six charting singles, some of which still get radio airplay over four decades later. (And all the songs on the soundtrack were written for the movie; it wasn't a collection of already-existing pop songs.)
Yes you can! For example, The Bodyguard. Shite movie, second best soundtrack of all time and possibly the buggiest selling, I know it was at one point.
"you can’t make a great soundtrack for a mediocre movie."
The Hackers soundtrack made more money than the actual movie. There was a sequel to the soundtrack but not the movie and unless you are involved in development, almost nobody knows the movie but you still hear songs from the soundtracks at nightclubs today.