Being successful is not about being smart or competent.
Most jobs in modern society require an average I.Q. and with most jobs, the skills can be taught. So people hire for likability instead.
Most people have average likability, including people with Mensa I.Q.s.
As a person with genius I.Q. and average likability and average success, I think that being successful is less about intelligence and more about schmoozing and selling and personality and being hyper-likable.
I wish there was a test to measure how good one is at schmoozing. The Schmooze Quotient. I bet that would be a much greater predictor of success.