I don't know. To me, it seems like you are oversimplifying things. I know a lot of Superman fans want to say
IT'S ALL SINGER'S FAULT (it's easier than saying:
my favorite character got owned at the box office)
! In my opinion their are a lot of reasons that were contributing factors to SR not making Spider-Man type numbers. I'll just throw out some possible ideas here (I'm just speculating), you can take them how you want:
1. Superman just isn't perceived to be cool anymore!
Is there a greater crime to a teenage audience than to be uncool? Spider-man and Batman are seen as cool by most of the general audience. Spider-man is the relatable superhero. Batman is the ultimate bad***. Superman? He's
the lame boyscout. I've never had to defend Batman or Spider-Man to my friends (in real life). Superman? All the time! My girlfriend, who is absolutely the sweetest person I've ever met, a person whom I have never heard say anything derogatory about anyone, has no problem making fun of Superman (I admit, she does it partly just to razz me, but I still like her

) . My best friend who saw the movie with me shares this attitude. I asked him what he thought after watching SR, this is what he said: "Well, I still think Superman's lame...but, it was a pretty good movie." He liked the movie, but he still felt he had to preface his opinion with the idea that Superman is lame. That is how deeply engrained the idea is to many people. That is an attitude that Singer did nothing to create, but is having to deal with.
2. The "Been There, Done That" Attitude!
Superman has been done so many times it is remarkable. Spider-Man was the first time audiences got to see a huge big budget spectacle about that hero. SR is definitely not the first time audiences have gotten Superman. I think this attitude also was partly responsible for BB average box office. I honestly believe Superman has about as many beloved incarnations as any fictional character around. The Fleischer Cartoons, The Adventures Of Superman, Superman 1-4, Lois & Clark, Smallville (I'm not even mentioning them all, just the ones most people are familiar with). I think a lot of people thought: "Superman? I've already seen him a bunch of times before." Even the second Spidey movie didn't make as much as the first one.
3. The Marketplace is FAR more flooded!
In the 70's, if you wanted to see a big budget, epic superhero movie, you couldn't watch Spider-man, Batman, the Hulk, the Fantastic Four, Ghost Rider, Daredevil, or anything else like that. Superman was the only game in town. I think that makes a huge difference. It just isn't as big of a deal for a new Superman movie to come out because we see superhero movies all the time.
4. Inherent "Problems" with the Superman mythology!
If you are like me you have probably known people who scoff at some of the basic things that occur in Superman's world. "How come nobody recognizes him as Clark Kent? He's just wearing a pair of glasses! That's so stupid!" Also complaints I've heard include: the spit curl and the underwear on the outside of the pants. If you are a Superman fan you take these things in stride. Singer opted to include all of them in SR because they are classic elements. But what do you do if you are a general audience member? One of the great things about Smallvile is that it doesn't have to deal with any of this stuff. There is no ridiculous costume complete with underwear on the outside pants or a spit curl. There is no glasses disguise because he hasn't officially become Superman yet.
5. POTC 2!
Seriously, did Spider-man, or Batman (1989) have competition anywhere near as stiff as this? Also the fact that Disney opened their movie this close to SR tells me exactly how they figured the general audience would react to a new Superman movie. POTC 2 had popular characters, popular actors, and was a sequel to a well received, popular movie.
I think I could go on with more reasons but I think you have the idea. I don't mean to completely absolve Singer of any responsibility. I've heard he had a lot of influence on the marketing campaign. I think the marketing could have been a lot better as far as reaching out to the general audience. Also as far as the film itself, if it would have had more action (I'm just speculating) it could have gotten a little more repeat business. I know it might be easier to say
IT'S ALL SINGER'S FAULT! I just think there are more factors to consider. Sorry for being so long-winded. If you took the time to read all this, thanks!