[Willi Berg]

It's not just kryptonite that can defeat Superman. Other Kryptonians equal his power, monsters like Doomsday can defeat him, he's been mind-controlled by Maxwell Lord. He can be emotionally manipulated- that can stop him. There have been many other ways. You can't just rely on kryptonite as the solution all the time. I think it should show up at some point but the writers shouldn't have that to fall back on every time and whenever possible come up with something else.