Why is the income earned by the footballer - who has a remarkable skillset by virtue of being a top footballer with all the training, fitness, skill, talent and determination - deemed to be as undeserved as the fluke of being born to somebody rich?
Salah's paid that much because he's a remarkable player who generates wealth for the companies that pay him - the club through winning, through PR, through ticket sales, merchandise, making the club appealing to both future players and those who will never be that skilled but love what he and his club stand for, and the other companies because his endorsement leads to increased revenue.
The other just exists.