At the same time Li Lin was speaking, the high-ranking officers of the Charlemagne Army were perfectly exemplifying his statement.
Planning march routes and supply channels is the very foundation of military command, and it's not just a matter of tactics—it's a decisive strategic factor. Throughout the history of warfare, the side with more ample supplies has a much greater chance of victory over the one with scarce resources. Armies lacking food and clothing defeating well-supplied armies is only an unusual case in a handful of examples.
Even Charlemagne, who championed the superiority of spirit, understood this principle. The officers who boasted that spirit could triumph over material also knew that without bread, the army could only choose between mutiny and collapse.
However, understanding and striving to solve the issue is one thing; whether one can overcome the challenges is another.