You have a massive survivor bias in your example of greatness in sports.

The odds of achieving greatness in sports is very low. If you come from a rich background, and want to maximize your chances of having a well-paying career, you do not go into sports. You go into law, or medicine, or banking, etc. Sure, the top players get paid well, but then look at what, say, minor league players get.

But if you come from a poor family, then sports is one of the ways to get out of poverty, because even if you can't go pro, there's still the chance of college athlete funding or becoming a coach for a school.

Engineering is similar, though less so.