[jammies]

I'm sure that is somewhat the case, Troutman, in the sense that boys who would want to be warriors, instead decide to try to be sports stars.

I would say the deciding factor is that violence has lost profitability in the developed world. You can't set yourself up as a warlord in Kansas, so the struggle between different factions promoting their own Big Man doesn't occur; however in Somalia that struggle continues and deaths from war are doubtless much the same hazard as they ever were. Similarly, murder rates decline because it is much more difficult to successfully kill someone in order to take their wealth, usurp their position and enslave their family, so instead the morally vacant become corporate officers, investment bankers and politicians instead of killers.