This topic seems to come up quite often. I personally don't know whether an investment banker contributes more to society than a motor engineer. However the expected income for the i-banker seems to be higher. I.e. this is an incentive problem. People can talk all they want about the intrinsic satisfaction in producing actual goods, but at the end of the day we all need to pay rent, eat, pay back student loans, and spring for the occasional round of drinks.