They can but at the same time when you have a shared universe, artistic compromises HAVE to be made to accomodate the big picture. The MCU is great for the most part but their films have a uniform feel because each director needs to comply with the building blocks put in place. If director X wants to tell a really crazy, bold Antman story, director X cant because Antman’s playing a vital role in a future team up movie. So I would rather DC remain a place where directors like Snyder or Wan or Jenkins or Reeves can come in and let their own unique visions be the driving force instead of having to comply with mandates. And hey if one vision doesnt work, no harm no foul because it wont spoil the whole broth.