[milchek]

Perhaps OP meant that the military industrial complex will always ensure wars happen?

Incentives are there to make money from weaponry and defense contracts. Further incentives are there to take land or resources, or to simply destabilize competing nations. To stop all of this requires a pretty fundamental shift in a human machine that is still hardwired for survival.

[TheAlchemist]

Nope, I mean humans are like that. We always want more, we are jalous of what another one have, there are countless unsolvable issues involving race, religions, history.

Sooner or later those transform into wars, inevitably. If by some miracle you could get all nations to agree not to arm, that would work, but of course it's unrealistic. As soon as there is 1 that don't agree (or worse, agree but arm secretely) everybody needs to arm as well.