Let’s suppose that you work in an office from 9-5 for 5 days a week. Let’s also suppose you are either an artist who sells drawings or paintings, a musician that does local concerts, or an athlete that participated in weekend tournaments that offer cash prizes, etc. now having a 9-5 lifestyle you would identify with the job you do 5 days a week and the things mentioned are things you “do on the side”.
Now someone else who does not work 9-5 would rightly call themselves a professional in the above things mentioned and seek to do it full time even if they made less money. They would spend all day drawing things, practicing their instrument and seeking as many gigs as possible, practice their sport full time and yet as many tournaments as possible and also seek sponsorships. The simple reason is that they make money and at the very least have a chance to make money. So they would see this as a career and not “something on the side” as someone who works 9-5.
So when someone has cognitive dissonance they don’t see themselves as truly successful even if it staring them straight in the face because they have been brainwashed by parents, teachers, and supervisors since they were children.