Why do modern wars kill fewer people than they used to?

First, the equipment is better now, soldiers have bulletproof vests, armored vehicles, tanks, GPS, and so on, effectively increasing the ability of the individual soldier's combat protection and danger avoidance.

Secondly, the medical equipment is now better, in the past, many soldiers died in the Second World War because the medical technology could not keep up with the casualties.

Thirdly, weapons are now more sophisticated and precise, so collateral casualties can be minimized.

Fourth, the tactics are better now, after so many years of war experience, there is a systematic military tutorials, optimized tactics, effectively avoiding unnecessary casualties.

Fifth, now the general launch of the basic are local wars, rarely have the strength of the equivalent of the large legions of fire fight, are asymmetric fighting mostly, so also reduces the casualties.

Sixth, now the rule of law gradually sound, are talking about humanitarianism, preferential treatment of prisoners (hold up to be abused a little, unlike the Japanese like the massacre of prisoners), so the general situation, see the situation is not right on the whole division of the whole army surrender (Iraq, for example). There are very few cases of fighting to the death and fighting a war of attrition like in WWII, which also greatly reduces the number of casualties.

The above factors, I do not know whether the owner's appetite.

(personal opinion, for reference only)