Lethality of weaponry has a significant impact on how battles are fought, where increasing lethality generally means fewer participants and, counterintuitively, fewer deaths: https://acoup.blog/2021/02/26/fireside-friday-february-26-20... is a decent discussion.

There's obviously some lag (the bloodiness of WWI) but overall yes, in a weird way, the Gatling gun and other weapons like it are part of why you're a lot less likely to die as a draftee today than in the Napoleonic era.

WWII was even bloodier then WWI.

The obvious difference between current draftee and Napoleon one is that Napoleon set up to conquer other coutries. The peace time draftee is going to have lower mortality.

Napoleon was literally the aggressor.

WWII's civilian/military casualty ratio was way higher than WWI's (~2:1 vs. very very roughly 1:1 or lower), which would affect how the lethality hypothesis affects casualties. When more of the dead are civilians and civilians predominantly die from famine and disease, higher overall death counts in a more-global conflict don't necessarily mean that conflict killed more soldiers per-capita, though some nations definitely suffered higher per-capita military losses due to factors beyond increasing weapon lethality - mostly thinking of Russia there. For instance, furiously crunches Wikipedia numbers in the UK it looks like WWI had a higher proportion of military deaths to population (~2% vs. ~.8%) even though it also suffered significantly more civilian deaths in II, though not enough to outweigh the decrease in military losses as a function of total population.

There might be an argument that increasing weapon lethality can decrease the number of battlefield combatant deaths but also could increase the likelihood of mass civilian atrocity. That said, high-lethality weapons definitely aren't necessary for mass civilian atrocities either.

And sure, I intended a wartime/wartime comparison regarding draftees: even if we go back to WWII as the last real great-power hot war, a French Napoleonic draftee (looking at France as Britain apparently didn't actually conscript in the Napoleonic wars) is significantly more likely to die in battle than a French WWII (or even WWI!) draftee: https://en.wikipedia.org/wiki/Napoleonic_Wars_casualties#cit...

The mere threat of its awesome killing power made an adversary think twice. In one of the most bizarre episodes Ms. Keller recounts, on July 17, 1863, during the draft riots, the New York Times (which supported conscription) mounted three Gatling guns on the roof of its headquarters, with the editor in chief at the trigger, and successfully cowed an angry mob without firing a single shot.

Armies are smaller because drafting ten million half-trained teenagers to carry rifles is no longer the best way to win a war.