If we are going to speak in absurdity and absolutely, it isn't going to be a real discussion. Yes defense can be just an important as offense. Hitting a homer can be canceled out by letting a baseball go by you because you don't have range, or not having the arm to throw someone out. A run is a run, no matter how it is scored, or even prevented. Your argument would be that a guy like Ozzie Smith was basically worthless because he didn't hit homers and put up RBIs.