That's one of things that actually made me sad watching the Death of Superman Lives... no one seemed to be that excited to be making a Superman movie apart from a select few.
It's interesting that Mario Puzo wrote the original screenplay for Superman 1 & 2. Puzo is better known as the writer of The Godfather triology. I guess WB made him an offer he couldn't refuse.
Maybe hiring competent writers also helps. The writers of Superman Returns also wrote X-Men: Apocalypse, which got worse reviews than Superman Returns.
RT 48%/66% for X-Men: Apocalypse compared to 76%/61% for Superman Returns.
It seems like they constantly chose screenwriters who have no affection for the character. It's simply an assignment.