Actually thes two parts do exist in tandem, it's just that those engineers/designers (a role you that can do the same) are usually independently successful and

Actually thes two parts do exist in tandem, it's just that those engineers/designers (a role you that can do the same) are usually independently successful and have repeatedly built high revenue products or started a company themselves. The major flaw i see in manager/corp/team analysis of workers is that it misses out on a portion of the population that is genuinely independently functional and creates and shares the value they create. They don't work for companies because they either don't need to or own their own. These are the ideals worth keeping in mind.