The truth is that good ethics sometimes is good business, but sometimes it's not. It depends on one's goals and how one defines good business. Sometimes, good ethics can end in bankruptcy. Of course, so can bad ethics. A fairer statement is that good ethics can be a very powerful business asset and that good things tend to happen to companies and individuals that consistently do the right thing and bad things tend to happen to those that even occasionally do the wrong thing. But the crucial point is that the moral obligation to live according to ethical principles is not dependent on whether it's advantageous. People of character do the right thing in the pursuit of virtue, not self-interest.
Never underestimate the power of temptation to disarm your better senses. Throughout the ages good people surrendered their honor for the empty promise that wealth or power would bring fulfillment and their dignity, good name and self-esteem for the passing pleasures of sex and drugs.