Gotham is a poor and corrupt city by the same inevitability that makes Joker immortal. We have no idea that Bruce isn't doing a lot for charity off-panel here, but that won't amount to anything for the reason that they can't show Bruce-without-Batman being more efficient than Bruce-with-Batman. Every reader is aware that irl, Bruce would be able to do a lot more if he went in politics or if he did charity or reorganized Wayne Enterprise and/or Gotham on a big scale than as Batman; DC isn't going to lampshade it any more than they have to.