Before the industrial revolution, people's wars were more difficult to wage, there were simply fewer weapons. And the civilian population was also slaughtered

Before the industrial revolution, people's wars were more difficult to wage, there were simply fewer weapons. And the civilian population was also slaughtered in the past, even if it was mainly mercenaries who fought, e.g. Magdeburg in the Thirty Years' War. I doubt there was ever a golden age of war.