Rather than putting a cap on what anyone earns, maybe it would be better to require that a certain amount of earnings over "X" amount must be donated back into the ENTIRE society that allows illiterate people of brawn, along with those who make a lot of money reading lines someone else had the brains to come up with, to get where they are.
That way people of certain music genres who can't seem to not get arrested for drugs or violence, along with athletes who don't have the common human decency not to mention the intelligence not to torture small animals, won't just be judged by their deficiencies as human beings. They seem to think that having "bling" buys respect, so let it.