Corporations exist to make profit for shareholders - since shareholders (the generic blob of shareholders represented by Wall Street) are only interested in short term profits and dividends then their prime motivation is money.
The implications are obvious. We shouldn't just jail the bosses, we should jail the shareholders. Or at least fine them.
Despite the icon, I'm halfway serious on this one. The bosses do what they do because the shareholders allow, even encourage, them to do so. If you knew you might be fined for voting a psychopathic shithead onto the board, perhaps you'd be a little more careful.