Most confusion comes from seeking a one-way trend, as in "is there
more or less war than in ancient times?" Problem is: overall, warfare
increased, then decreased.
Yes, most of the "tribal" societies that anthropologists study have
high rates of war. But most of these are intermediate forms between
very distant ancestors and very modern societies, with many relatively
...War was hard for foragers, as
hostile victims were far away, at unpredictable locations, and with few
physical goods worth taking; women taken in war could easily escape... Increasing density made targets easier to reach and find,
and marriage as property made wars to grab women more tempting.
Herding helped attacking armies to travel further and faster, while
farming created more tempting and harder-to-defend targets to attack.
War is hell, not an especially modern hell, but also not an especially ancient hell. War is most distinctly, a farmer's hell.