Uchiha Chi continued, "The end of the First Shinobi World War wasn't because the participating villages had exhausted their military potential, but because the regimes of the various hidden villages became unstable after the deaths of the First and Second Kage, leaving them unable to continue the war.
As the Third Kage of each village suppressed political opponents, eliminated dissidents, stabilized their regimes, and accumulated strength to their peak, the Second Shinobi World War finally broke out. That is why there was such a long interval between the first two wars.
However, not a single Kage from any of the villages died during the Second War. Instead, the war actually made their respective regimes more stable than ever.
Chapter 60