Your question is built on some flaws in logic and definition.
First, “passing” is a wide range... from people who did just enough to get by - one point over an “F”, for example - to those who aced the class. There is a big difference between “passing” and excelling.
Second, schooling in only one factor in success. Character, curiosity, honesty, integrity, creativity, perseverance, intelligence, work ethic, and interpersonal skills are at least as important as education. Think of an education as the MINIMUM requirement.
Finally, one’s level of education is not directly linked to a higher income -and certainly not to being a millionaire. If so, college dropout Bill Gates would not be one of the richest people in America. Mr Gates has those OTHER qualities... do you?