re: expendable numbers
I think one big difference between now and then is the draft. I don't believe in mandatory government service for any reason, and the volunteer army is working pretty well right now considering the war.
Back then, people were dragged into the military. I wouldn't think much of that either. It has been noted that when the draft stopped, so did much of the protest movement.
I hear a lot about "planning." There were plans going in. The circumstances changed, and so did the plans. There is not a war in human history that has gone as "planned."