Prior to the invention of the radio, lower level commanders always had to use their initiative when commanding their troops, because there was no reliable way to quickly communicate with their commanders during a battle.
It's disappointing this was missed, because it's an important point: Control needs to be proportional to communication.
Also:
They also were taught to live off the land by hunting and foraging. This decoupled the soldiers from the slow supply caravans and allowed them to remain independent for long periods of time.
The author probably should have pointed out that this tactic led to his armies in the Iberian peninsular being bled by attacks form the local population sick of having the crops stolen by "foraging" soldiers. It also led to the Russian disaster - the Russians left nothing for the French armies to forage, and so when winter came they ~all died.