Wars
>"Isn't it odd that in an age where every man could be called on to fight, and where combat was face to face, man to man, wars were just as common as they are now? "
Yeah, it seems to be in the history of this planet. Perhaps we continue bigger and better and more deadlier weapons until the whole race balances on the edge of extinction.
However, I just had a brilliant insight on how to stop or slow down all wars. Castrate all males at age ten. Teach them music and literature.
(Keep a good select sperm bank as well.)
Let women rule the world.