with an aggregate function like an auto manufacturer, you'd want the executive in charge of each constituent function to be competent in that area. The CFO should be well-versed in accounts, the head of design should have been a designer, the head of factory ops should have experience and knowledge of how a factory works, and so on.

The CEO is an awkward one because they can fill different roles in different companies, but I guess CEOs are usually people managers first and foremost so it makes sense for CEOs to come from the management chain.