Interesting analogy with the driver/car.
The frontal lobe is the last part of the brain to develop and is usually still making connections between different parts of the brain into the mid-20's.
The idea of "executive function" is kind of like the idea of "the mind". We know we have a "mind" that exists in some way separately from the component parts of our brain and nervous system. But where does it exist? Is it in a particular place in the brain? How does it work exactly? We know we have one based on the evidence but defining what it is and is not, how it works, etc. is really hard to do - like holding a cloud in your hand.
We know the abilities/skills/talents we now call executive function exist. People who have really good executive functioning are more likely to be successful in life than those who do not. But when you start trying to define exactly what it is and is not, when it's working and when it's not, how to fix it when it's not working - it can be a lot harder to do than you would think.
The concept of executive function doesn't take into account individual differences between people very well in my opinion. Identifying good vs. defective executive functioning is culture-dependent: the evidence for good executive functioning in our culture may not look the same as it does in an aboriginal one for example. More effective executive function also seems to rely on greater self-awareness or ability to recognize when our executive functioning could be better, figure out what to do differently and then make attempts to improve our functioning. A conscious feedback loop exists that allows us to learn from our mistakes and I think that also belongs under the umbrella of executive functioning.
