Great stuff. The battle was all about maneuver, but the war was all about logistics. It is a minor miracle how Hannibal managed to keep the thing going for a decade with minimal reinforcement, up and down the Italian peninsula with a slowly dwindling number of troops. But the notion that the Romans didn't win any battles is mistaken. The pivotal one of the war was not at Cannae, but at the Metauro river some ten years later, when the relief force under Hasdrubal that would have reinvigorated Hannibal's effort was soundly defeated in the
Battle of the Metaurus. After that it was just a matter of time before Hannibal was recalled.
Hannibal found about the defeat of his brothers army at Metaurus, when his brother, Hasdrubal’s, head was thrown over the wall into Hannibal’s camp