I agree with you that a movie with minor characters can be awesome. I don't agree with you in that a movie like that can be succesfull. As simple as that. Why is that contradictory? Great movies bomb all the time.
I'm saying the public won't be bothered if Superman and The Bat-Man aren't in the film, but that doesn't mean you can put whoever you want in it. They have to be major superheroes. Considering that, I personally think they might as well put Supes and Bats.
The stats I posted are not movie specific, but I'm fairly sure that going to the movies counts as "consumer decisions". And of course they don't account for the whole world... this may come as a shock to you, but stats never do. Yes. Yes, it's true. The people who make stats only interview a bunch of thousands people and use them as a sample to create larger conclusions. That's what stats are, conclusions based on samples. You asked me for stats, you got stats. Anything else?