Why Don't More CIOs Become CEO?

jcatcw writes "Thornton May is mystified by the very small number of Fortune 500 companies that led by former CIOs. "Knowing what we know about CIOs — that is, that most are smart, hardworking, supremely aware of how the business works and increasingly savvy regarding the workings of external customers' minds — the failure of more CIOs to become CEO has to be one of the biggest mysteries of our age.""