Of course, these differences are almost certainly made up of many different components. Having a positive effect on many different components is the only way to account for the 40% power improvements we tend to see, on average. There is no one component that can account for that amount of improvement.
He is wrong or you have interpreted what he says wrongly. Even though lots is going on, balancing and walking and running and cycling involve essentially no "brain" power since this is entirely accomplished at the level of the cerebellum and below. The higher brain is only involved if something need be changed such as initiating the action, stopping it, changing effort, changing direction, avoiding an obstacle, etc. My point is that once these patterns are ingrained they are exceedingly difficult to change but change is not impossible.
There is no one huge thing. It is why those who state that how hard one pushes is the only important thing are way off base.
Hogg is trying to sell an arch support system. He does say this: "The answer is to change the quality of the stimuli from the feet so it can be 'heard'.In other words to metaphorically raise the voice of a speaker at the party or to metaphorically tug the jersey as per the examples above."
Well, my point exactly when it comes to changing pedaling style. It simply is not possible to expect the rider to be able to change unless there is adequate awareness of what he/she is doing. That is the point of the PowerCranks, to give the rider the awareness of when they are doing it correctly (according to us, anyhow) and when they are not. Then there is a real chance of changing. Without adequate awareness of what one is actually doing it is not possible to change.
The question remains, however, Is the PowerCranks way superior to what most do "normally"? Or, is there another way (linear technique?) that is superior (how would one train it)? That question remains unanswered scientifically.