If I'm reading this correctly, this can be summarized with the principle-agent problem. Getting the cupholders right doesn't have incentives that line up with their relative importance for the car industry - my guess is that a large part of it is being a less prestigious work assignment. This is based off of "if I was really into cars, what would I want to work on?" Engines, aerodynamics, and control systems top the list - lots of complexity, and it's something that is obviously difficult to get right (hence, you must be an awesome engineer if you can get it right).