Draft-dodging was a fine art during WW II. Read any of Paul Fussell's excellent books (especially "DOING BATTLE")
Burkett's book supports what you say. According to Burkett ("Stolen Valor"), the volunteer to conscript ratio was *higher* in Vietnam than either WWII or Korea.
True- but then, whenever and wherever there has been conscription, men have found ways to avoid it (from paying their way out to shooting off their toes). I have no doubt that this sort of thing was widespread even in some of the cultures we consider to have plenty of martial virtue- like Sparta, or the Plains Indians. Cowardice is a VERY common human frailty.
Someone should write a book on this...