Philosophy is about finding your deepest assumptions. For most people, these roots lie unexamined. People believe what they believe because of socialization or wishful thinking or isolated personal experiences. Their ideas may not even be consistent.
Philosophical debate forces us to reveal our assumptions and check the consistency of our beliefs. Though debate might never result in one party accepting all of the assumptions of the other, it can reveal what those assumptions happen to be.
Thus, success in persuading others to one's philosophical conclusions isn't the true measure of one's philosophical progress. That progress is measured by the philosophers' deeper insights into eachothers' assumptions and reasoning. In other words, I will continue to find satisfaction in the philosophy game as long as I continue to gain deeper insigt into my axioms and the axioms of the other side.