Further to that point, there hasn't been a serious war between major powers in seven decades. One of the longest stretches in recorded history.

Overwhelmingly what we've seen in the way of war deaths since WW2, is in civil war and genocides by Socialist, Communist and Fascist regimes.

Don't forget that the US has had a hand in very many of those wars, and have been responsible for massive amounts of deaths in Korea, Vietnam and Iraq.