vesicles
Colonel
Good points, although I think it would be much harder to track foot infantry than armor columns. However, the ability of the advanced army to call in reinforcements and airstrikes means the infantry army can never win in a stationary fight.
However, could they possibly rely on raids to completely disrupt enemy supply lines? If that could be accomplished, they can simply starve their enemies into submission.
One or two battles, perhaps. However, the opponent can simply strengthen their escort to counter surprise attacks.
Additionally, this kind of surprise attacks can only be accomplished with small number of troops so that they wouldn't be detected before the attack takes place. With the small number, they can't achieve much even if they succeed. How much supply can a few light infantry foot soldiers take away? If they want to take more, they would have to bring heavy equipment, which will slow them down and increase the possibility of being detected.