The problem is that it's very difficult to measure "value" objectively in monetary terms - particularly for senior positions tenuously related to the productive activities of the business.
That problem is compounded by the fact that there is deep-seated human tendency to confirm their prejudgment by seeing things that aren't there. There's a famous experiment in which subjects are asked to estimate the height of someone standing in front of them: if you first tell the subjects that the person in front of them has a position of seniority, subjects will estimate a greater height than if they think it's an ordinary grunt.
There's a very real propensity to appoint people to jobs who look and act like other people who have held similar jobs before. Even more, there's a propensity to create roles that other organisations have, whether or not your organisation actually needs them, because you want your organisation to look like other credible businesses.
That's why you get a bunch of the usual suspects trotting between similar jobs, even when they've a record of spectacular failure. Along with the fact that investors feel more comfortable with people who fit the mould of people they've worked with before.
When it comes to the two main drivers of human behaviour - money and sex - don't expect logic to trump perception.