I'm not sure how you'd gauge that at all, there are so many skills that could qualify as "raw ability". Is it just turning the wheel and making your car faster in the turn than others? If so then that's just as important as leadership/keeping your team motivated, giving good and meaningful feedback that the CC understands, consistency, staying calm, endurance, strategy execution (saving fuel, tires), focus, planning out passes, etc., the list goes on and on. Why focus on just one of many skills that makes a driver better than his opponents.
The goal is to win races and titles, there are more factors that increase or decrease a driver's chances of achieving those goals than "raw ability". Saying a handful of drivers could do what Jimmie did is flat out disrespectful. Not only because Jimmie has more "raw ability" than you give him credit for, but he has the total package a racer needs.
What many fail to realize for whatever reason is that great drivers can't achieve great things without great crews, and vice versa. A great crew chief is nothing without a great driver that can go out and execute, and describe how the car feels and what needs improved. Having a great crew chief and a good "set of circumstances" shouldn't knock down any driver's achievements, and having what is assumed to be lesser crews doesn't excuse finishing behind a team that has the presumed advantage in that regard.
