I understand what you are trying to say, but your argument does not hold up. I contrasted your weapons of WWI with a more modern, and presumably "cleaner" weapon from the 60s. Or how about that clean killer from WWII: napalm? I'll take death by WWI shrapnel any day. War was, and always will be, utterly brutal.
Excellent post!
The use of massed troops persisted in WWI, on the allied side. Late in the 19th c, after a few decades of relative peace and quiet in Europe, German military thinkers looked at the prospects and realized that, should a general war break out, Germany would be outnumbered perhaps 4:1. They changed their entire military approach, designed and built the first modern artillery pieces, and substituted firepower and ammo for food in the soldier’s field burdens. At mealtimes, either troops were rotated, or food was brought up.
The German army had everyone way outgunned by the outbreak in August 1914. And the Austrians contributed giant siege mortars capable of destroying pretty much any fortifications in Europe.
French thinkers had realized that, given the scale and sprawl of military formations, the era of single decisive engagements was basically over. The British didn’t agree, and apparently still haven’t figured it out. Their generals used massive physical assaults against superior firepower and artillery until their armies were gone — then raised another and another. The British could and did call on their overseas empire to furnish cannon fodder — names from the Indian subcontinent can be seen on the monument at Gallipoli; as in WWII, Canadian troops were hurled into some real hornets’ nests. The other sources of more manpower were Italy and Romania, which Britain talked into entering the war, with disastrous consequences for each.
Throughout WWI, and to this day, the British maintain that the Germans in WWI were “running out off men”, basing their estimates on their own (UK) losses. The fact was, German casualties and deaths were a fraction that of the pre-1917 allies’. The French, of all people, had figured out the mistake, and also figured out what to do about it, yet didn’t have the manpower (or a decent one-man field weapon) to do anything about it — however, the French training came overseas and helped the US in what was one of the fastest huge mobilizations in our history.