I also think it’s abhorrent that anyone can earn that kind of money from playing a game. And worse are the executives in charge of the clubs/associations. The Saudi league for example?
But that's capitalism for you. It's unfair to single out football. Look at big corporations where the CEOs earn millions while those at the bottom struggle on minimum wage. As pps have said, look at those with inherited wealth who do precisely fuck all for their money.
Salah has a skill that can command an exceptionally high wage. He has presumably worked his way up the football ranks, trained intensively and so on. It's a matter of luck for him that his skill is worth so much, and a matter of market forces in a capitalist society that make it so.
In the wider sense, capitalism is indeed abhorrent, but individual footballers are not abhorrent for simply taking what is been offered in a system they can't change - again, as pps have pointed out, Salah has been using at least some of the money charitably.