Nature had campaigns ebb and flow, due to iceages and warmspells, had island holdouts being wiped-out by systems adapted to furious combat on continents (invasive species).
Your picture of nature is very much distorted by a rejection of a rather cthullian reality.
What you mistake for peace is a coldwar equilibrium, where all sites furiously roll the dice of research for new war-tech- and then humans came along. Humans are very much a natural system doing natural things, very successful though.