This was my initial thought as well. But on further thought, it doesn't seem to be true. I think, with technology and inter-connectivity, we are getting exposed to diverse points of view more than ever before. It might eventually lead to one culture, but then that would be because we all learned from all the options and settled on the best combination.
Oh, each human being is definitely exposed to more diversity, but that doesn't mean the world is getting more diverse. Now, I can be English and interact with people who are French, German, American, Chinese and so on; previously, I could have spent my whole life only interacting with Anglo-Saxons, but not know about the Bretons, Picts, Gaels, Geats, Swedes, Goths, Navajo, Hopi, Anasazi and so on nearby and around the world.
Perhaps we'll settle on one culture as we choose the best one. I more imagine we'll end up with one culture in an endless echo chamber, forever unable to sense our own biases.
