I'm not sure history bears out that major wars lead to peace. WW1 led pretty directly into WW2, and after WW2 there were plenty of conflicts by major powers. That major powers didn't start WW3 (to date) probably has more to do with the potential consequences threatened by nuclear war than an increase in human aversion to widespread industrial war.

There's probably an argument for European countries specifically not wanting to return to the near-constant warfare across its history. But I'm not sure that holds for US v USSR (which came perilously close to open warfare several times), or conflicts elsewhere.