[...] they'll probably target one anothers' civilians.Which would be a first class war crime.
Nations are never going to rid themselves of the desire for war, or the need for war to involve bloodshed, because we're just another species of simian bludgeoning the out-group to death with extremely abstract and over-engineered rocks.
While that is not an uncommon point of view empirical evidence suggests otherwise, war seems to be in decline and seems to have shifted from wars between nations to civil wars and asymmetric wars.
Some argue that advances in human behavior heavily lag behind technological advances and I tend to agree at least somewhat, but concluding that we will never manage to overcome this stupidity seems not really obvious to me. And I certainly hope that it is not true.
We already have non-violent ways to resolve conflicts between nations, we fight wars explicitly to kill people.
Force is the ultimate and only way to »resolve« conflicts if all other means fail. But I do not think we are killing people for the sake of it in wars, it is just a means to an end.