Watched part the rerun of the PBS series WWII. They stated the percentage of troops that actually saw combat. Can’t remember the number but it was surprisingly small. 5%?
It's been said that ‘amateurs talk tactics but professionals talk logistics.
An army can't continue to fight without the support.
That's exactly why Eisenhower was put in charge as supreme commander during WWII. He understood what was needed to support the troops engaged in combat.
Most people don't know that Eisenhowers rank as a five star general wasn't a permanent rank. His permanent rank was as either a lt. Colonel or full Colonel.
He was put in command strictly because he was the ONLY person fully capable of coordinating ALL aspects of the war, ESPECIALLY the logistics.
He alone had the tools to ensure that the troops who needed the supplies got them. He understood how to keep the supplies flowing and how to distribute them.
He was never recognized as a great tactictician, but a great leader capable of bringing all the efforts together to achieve the necessary results.
Left to their own devices Patton and Montgomery would have taken the vast percentage of the war material leaving the other efforts starved. Patton and Montgomery would have each pursued their own goals maximizing their own glory and the total war effort would have suffered.