Your logic/math doesn't make any sense.
Almost every student studies math, almost none of those ever become a mathematician - who are compensated much less than NFL players.
> There are about a million doctors in the US
Comparing # of doctors to # of NFL players is a very false equivalence. Try comparing # of athletes in all sports combined to number of doctors - that would be more reasonable. Or compare the number of brain surgeons to the number of NFL players - and the difficulty/time in becoming either.
Being a doctor is a much more stressful and difficult job, which requires more years of training/education and provides far more real value for society.