Why not, exactly? I'm not sure what your point about WWI was, other than to point out that once upon a time, upper class types volunteered be officers, in order to send poor grunts charging at entrenched machine guns.
Regardless, America, 2006 is a long, long way from America, 1917. Back then, everyone knew someone affected by the war. Nowadays, outside of more conservative circles, it's pretty rare. For most of my civilian friends, I'm the only one they know that's been to Iraq, and they consider that quite a novelty. Knowing a WWI vet in 1921 wasn't considered novel in any way.
Society was more class-centered then, true. However, this isn't all that relevant a distinction -- being an officer in WWI wasn't all that much safer than being a grunt.