Bruno didn't realize it, but the French had sent agents to Russia for the specific purpose of assassinating him. Instead, he was in the middle of readying his forces for the march on Tsaritsyn. It wasn't exactly something that could reasonably be handled overnight.
Establishing a logistical network took time. And considering the vast territory of Russia, and the largely barren wasteland that it was. Creating this supply line was an effort of monumental undertaking.
The worst thing you could possibly do as a commander is to become over eager in the pursuit of victory, and in doing so advance beyond your supply lines. It was a mistake that many nations had made in history, and nearly every time it ended in complete and total disaster.
And many of these instances had taken place in Russia itself. Whether it was Napoleon's march on Moscow, or Germany's assault on Stalingrad. Both ended in defeat, and the consequences of which ultimately lost them the war.
