One of the major themes of All My Sons is the corrupting influence of money and greed. Joe Keller's hunger for material success leads him to commit a crime, but Jim Bayliss, who serves as a foil for Joe, is corrupted by money in a more commonplace and relatable way. Jim is a highly-paid physician who hates his job and wants to do medical research instead. He believes he would enjoy this, and that he could do good work, but the change in jobs would involve a drop in salary. Jim would be happy to make this sacrifice for himself, but his wife, Sue, is adamant that he must maximize their income and status by continuing in his successful practice.
Jim realizes that he is making a mistake by deferring to his wife and her materialistic values. Apart from providing an example of how money can steer a life off course, Jim acts as a counterbalance to Joe's attempt to indoctrinate his son Chris in the gospel of wealth. He advises Ann:
When you marry, never—even in your mind—never count your husband’s money.
Jim, therefore, serves as an example and a warning that, even if you stay strictly within the bounds of the law, your life can still be marred by submitting to the greed that is endemic in society.