Just so happens John Keegan's marvelous book "The First World War" sits aside my desk next in line for a reread. Great comments, Griz. The paradigm shifting that occurred from the the Napoleonic Wars through the American Civil War to World Wars One and Two is at the same time fascinating and horrifying.
The War To End All Wars of course saw the first introductions in large scale war of the aeroplane, the tank , and the steel capital ship. All would prove transformative.
Re: Numerology. We can't completely discount the possibility that there are certain numerical schemes "baked into" the physical universe and/or human history, or even providentially superintended by a Divine Being as signposts, but most examples I have seen are arbitrary (and sometimes forced!) creations or superficial coincidences that say more about our penchant for marking significance in our lives and in history than about any compelling reality. They also put on display the brilliance of some people for finding them. The trouble usually crops up when it becomes clear that someone is trying to squeeze the square peg of reality into their preconceived, neat and tidy round hole system.
Either I didn't read the "License Plate" article correctly or it contains it's own refutation.