I think superstar effect might be valid if only one person is going to win. Clearly, some people have genetic and experience advantages that would take years for the superstar's competitors to achieve, and why exert the force given the implicit probability that you are going to lose is high? The situation changes where there are number of top spots. Sure there might be one or two superstars, but it is more likely that you would place in a top spot. I am talking about GE competition scheme with 20-70-10. I think, everybody would think that they can reach a top 20% spot. The employees would know some people are a guaranteed for those spots but the others are very much open to someone willing to work hard, so in this sense I don't think it impedes competitiveness.