A while back I finished Ford Maddox Ford's tetralogy Parade's End - a superb read. The four novels are set mainly in England and the Western Front in World War I, where Ford served as an officer. He vividly brings back to life the dirty, routine, mechanical ghastliness of trench warfare.
Here his main character Christopher Tietjens reflects with a peculiarly grim irony on the grisly inefficiency of it all :-
This was the war of attrition...A mug’s game! A mug’s game as far as killing men was concerned, but not an uninteresting occupation if you considered it as a struggle of various minds spread all over the broad landscape in the sunlight.
They did not kill many men and they expended an infinite number of missiles and a vast amount of thought. If you took six million men armed with loaded canes and stockings containing bricks or knives and set them against another six million men similarly armed, at the end of three hours four million on the one side and the entire six million on the other would be dead. So, as far as killing went, it really was a mug’s game.
That was what happened if you let yourself get into the hands of the applied scientist. For all these things were the products not of the soldier but of hirsute, bespectacled creatures who peered through magnifying glasses.
Or of course, on our side, they would be shaven-cheeked and less abstracted. They were efficient as slaughterers in that they enabled the millions of men to be moved. When you had only knives you could not move very fast. On the other hand, your knife killed at every stroke: you would set a million men firing at each other with rifles from eighteen hundred yards. But few rifles ever registered a hit. So the invention was relatively inefficient. And it dragged things out!
Ford Maddox Ford - Parade's End