It's sad that even the studio admitted Superman Returns didn't live up to their expectations either. They didn't even bother to try and salavage the film with a sequel
From Jeff Robinov 2008
"Superman Returns didn't quite work as a film in the way that we wanted it to. It didn't position the character the way he needed to be positioned. Had Superman worked in 2006, we would have had a movie for Christmas of this year or 2009. Now the plan is just to reintroduce Superman without regard to a Batman and Superman movie at all."
Really what else could we expect from SR?