IMHO That may be the initial/macro reason to sign up/drafted, etc. In the end, it's the guy next to you that helps generate the courage and the drive to succeed, i.e. surviving. Some sacrifice themselves for their "friends". For the most part, I suspect the guys comin' out of the Higgins or in the Ardennes were thinkin' about themselves and their buddies. They were interested in defeating that enemy soldier/unit and not defeating the Third Reich per se. I hesitate to bring this up on the internet because I don't want this taken as a troll point or an attempt to counter your point. It's just my opinion on a subject that's probably been talked about in every war.
Have you seen "They shall not grow old?" It's a WWI documentary by Peter Jackson that uses actual interviews with British soldiers as the audio track. They do talk about the sense of purpose that drove them to serve. Like many other soldiers, the ones who were interviewed didn't realize the horrors of war until they were immersed in it.
On another note, my father in law did talk once about receiving orders to prepare to go to Japan shortly after Germany surrendered. I couldn't imagine any point of lower morale for him and his fellow soldiers.
