I think his point was basically that every automobile made in the last 100 years already comes with an infinitely-variable control for engine output. From zero to 100% power, you have direct and instant control over how much you get and when you get it.
Want more power? Push the pedal more. Want less power? Push the pedal less. Want power sooner? Move you foot down farther and more quickly. Better economy? Don't accelerate as quickly. Not exactly rocket science here.
Maybe people have spastic feet and can't control the pedal -- I don't know. Subaru's "Sigh drive" is just as useless.