Answer
Two factors that lead to highly paid superstars are that all of the consumers in a market want to enjoy the good produced by the best producer and that there is a low cost to every consumer (usually a technological cost).
Work Step by Step
Dentistry and music would likely not have superstars for multiple reasons. There is usually a high cost associated with enjoying the goods produced by a dentist (although consumers do want to enjoy the good). There is usually a low cost in consuming the goods produced by a musician, but not all of the consumers in the market want to consume the goods produced by the best musician.
