I'm particularly perplexed by the claim that war would be solved by higher intelligence. Many wars are due to ideological priorities. I don't see how you can expect necessarily (or even with high probability) that ideologues will be less inclined to go to war if they are smarter.

Violence has been declining on (pretty much) every timescale: Steven Pinker: Myth of Violence. I think one could argue that this is because of greater collective intelligence of human race.