The reason why Superman will never reclaim his old glory or ever overtake Batman, is because he's not versatile and cannot be be all-encompasing. Batman can be low-level, high-level, as strong or weak as the story commands. He can be brooding and dark or bright and adventurous. He can wear armours or tights, he can have horror stories or spy stories or space stories. Superman can't. Because they won't let him. He can't change his costume. His powers are not flashy. He cannot carry some Kryptonian sword or board a Kryptonian vessel. Superman is just Superman and that's all he is. He cannot leave Earth and have space-farring adventures. He cannot even leave Metropolis. Superman is a victim of his own perceived importance. He cannot evolve or even be interesting, because he has to be a trite voice of reason for retarded 12 Y/Os and nothing more.