As you say, the threat of invasion was the only reason people banded together physically. Now the the threat is gone, we should see more (as small as possible)

As you say, the threat of invasion was the only reason people banded together physically. Now the the threat is gone, we should see more (as small as possible) city-states because everyone loves freedom and more control over their lives. There would not be a world government. Instead multilateralism is how the world would coordinate/cooperate.