As technology and writing developed, armies could be raised and commerce expanded. The number of languages, kings and gods became fewer and fewer, but each commanded the loyalty of its population. The process has continued up to this very day. While I believe that the process will continue, I can not be sure. Economic globalization is moving the world closer to unity.
International finance knows no boundaries.
Malaysia now boasts the world's tallest building and is planning two more even larger. They never could have done that with their own resources. While the percentage of the world's population living in abject poverty is still huge, it is declining. The danger is that loyalties to ancient creeds and cherished grudges among people will start major wars. Implicit in loyalty is the existence of an enemy.