Half of the population is something really respectable, but the problem was mentioned before: these are very heterogeneous nations with very different cultures and ideologies and interests that will not always be easy to reconcile.
Although this is not wrong but I think people are overthinking this. Obviously all countries and every people have differences and follow different cultures and ideologies, but that has never stopped them from forming alliances and joining a single bloc. Look at Europe for example!!!
Additionally there is one language everyone on the planet understands and that is money. So all these countries share a coupe of very important interests. Like improving their economic situation, creating a better security for their people, getting rid of the weaponized fiat (ie. dollar) issued by a government with the largest debt in human history ($37 trillion and counting), ...