People who steal successfully have done less work for more profit. Any child/ any adult can see this. I'd take another tack. It's not a question of work vs payoff.
There are lots and lots of people who make their way in the world by lying, cheating, playing politics, smooching their boss' ass, stepping on others, etc. They live in a world where they get lied to, cheated on, played, and trodden on, and they live in a state of fear because their means of making a living could easily disappear based on the perception and whimsy of their superiors.
There are other people who have worked hard to become exceptionally good at what they do. They don't have to lie and cheat in order to get by because their skills are in demand. They don't live in fear and are not surrounded by scheming, miserable people. They live much happier lives.
So that's what you should tell your son. I don't have any children btw. I'm just incredibly wise.