They are not supposed to be rewarded paid based on objectively measured merit. There is no such thing. Payment is compensation for time, or an exchange for a commodity, and the rate is based on the demand for said commodity or time. Go back to Hollywood, the best actors are not necessarily the highest paid, and their pay rates have little to do with availability, but by their perceived draw at the box office, and how badly other people are willing to pay for their time. If absolutely no one wants to hire the biggest star & most talented actor in Hollywood, the one guy who does can get him for the minimal possible salary and there is not one thing wrong or unjust about it.

And that goes for every other salary. Why are teachers so "underpaid"? Because it's not hard to find a warm body to babysit a room full of children and indicate which study materials they should peruse. Or look at sports in comparison to other jobs and each other. Why are baseball stars so "overpaid"? Because throwing or hitting a pitch is considered among the most difficult feats in athletic competitions. Football is certainly more popular and much more dangerous, but the requiste skills are more rudimentary and thus in greater supply. Hockey probably requires more skill than football, but is in much less demand, and so NHL players generally don't make as as NFL players do. It's the same thing with the US women's soccer players who have recently been whining about not making as much as their male counterparts. It's because worldwide, there is less demand for female soccer players, and in the US, there is relatively little competition for female athlete's participation. They can't go elsewhere for big bucks the way the men can, so the men's team must pay higher to retain or attract players. On merit, the women probably should be paid higher, but no one gets paid based on merit, they get paid based on the demand for the services or for their productivity. Hollywood and professional sports and juvenile educators produce very little of tangible or objective value, so they must be paid by demand.