He is not showing anything ground breaking.
ohgood, what you are saying is exactly what he is showing. Basically the difference the lean angle makes on the turning radius at the same angle of the bars. And yes, you are absolutely correct that EVERYTHING (speed, throttle, lean, bar angle) together is what makes the complete pictures and gets the bike around the cone fastest, without falling over.
Here he is just showing steering principle by itself, and of course the bike would fall over without the throttle and speed.
Also when he is doing the snake, its good to realize that bike can steer itself, based on the lean. So you don't have to fight with the bars to steer the bike.
Which used to happen to me all the time.
Again, this is just another look at all the foundations of motorcycle riding. Just a good illustration in pictures, rather trying to explain it in words to someone who might just be starting out with this.