
Originally Posted by
Fwahm
They can cooperate, but they can also regress and become warlike again. Once Naruto's savior effects wear off, all it takes is another Danzo, or 5th Tsuchikage, or whatever to start it all up again. If there was only a single large nation, it would likely take longer for regression to happen. Look at our current relationship with Russia, for example; after the cold war ended, we were decent allies with them, but now Russia is at odds with tons of people over Ukraine. Personally, I believe uniting the world would make such things much less likely in real life as well, though it'd be harder in real life than in the Narutoverse because of much more varied religion, culture, and languages than the mostly unicultural Narutoverse.
Sasuke isn't blaming the current Kages specifically. He's blaming the 5 nation system, and to get rid of that, killing off the current Kages is a necessary sacrifice.