It really didn't do that well for the amount of money put into it.
S:TM is overrated, IMO. The movie is so dated one of the reasons SR did poorly was it's connection to that movie.
The logic for C while I can see where you're coming from, is not entirely why people want to see a Superman film. Sure rescuing people is fine. However, if that's the best it is going to get, than that's pretty sad. You can do rescues and still have a great superhero/supervillain battle. I'm not saying every scene needs to be a battle scene, but having one may have helped the film. Most people I know who were disenchanted with the movie didn't like it for that reason and for giving Superman his Superson.
Are you aware that supervillains (and thus superhero vs supervillain fight scenes) only really arrived with the Silver Age of comicbooks? The original Superman stories never had any of that stuff.
Also, Superman Returns shows Superman as a messianic figure, a saviour. What he is doing is more than rescuing people - he's performing miracles. That's far more powerful and intresting, and true to the character, than a fight scene could be. Superman is not here to fight people, he's here to help.
This is how superheroes are supposed to work.
An innocent person is in peril.
Superhero in secret identity spots this, and hurries to change into superhero garb.
Race against time, suspense.
Hero arrives just in time, and saves person from peril in some spectacular way only they can.
Euphoria on the part of the viewer/reader.
That's how it works. The drama is not whether Superman will be killed, it's if the innocent(s) in danger will be killed, it's whether Superman can get there in time.
Superman Returns helped me understand this so much better.