"Success in almost any field depends more on energy and drive than it does on intelligence. This explains why we have so many stupid leaders"

This quote by Sloan Wilson suggests that success in any field is more dependent on effort and decision than it is on intelligence. This implies that intelligence is not the only element that contributes to success. It also suggests that even if somebody is not particularly intelligent, they can still accomplish success if they are willing to put in the effort. This could explain why there are a lot of "silly leaders" in the world, as they may have striven to get to their position, despite not being especially smart. This quote encourages us to concentrate on our own efforts and determination, rather than relying solely on our intelligence.