I think Europe and the Americas are differently heterogeneous and differently homogeneous. Certainly the Europeans have made more practical strides in building a coalition across their members than, say, South America or Central America. The reality is that Europe demonstrates a higher degree of solidarity between states than these other places. So it's strange to me to argue the opposite.
But if I understand, your assertion is that the Mayans, the islanders of the Caribbean, the people of Peru, or the Amazonians are less culturally different from one another than the citizens of, say, Greece and Norway? I'm not sure I buy it personally .. but I can see your argument.
not...really a solid argument for how well they would combine, but clearly a major contributor to how how much you know about them.
And FYI those languages didn't disappear 400 years ago. They are spoken today. Guatemala alone recognizes 25 current spoken languages - Spanish and 24 languages that are completely unrelated to any European language.
> For what it's worth a lot of cultural differences are becoming increasingly (unfortunately) minor differences at best because of globalization and the Internet and other communication technologies.
Good news! Many of these languages are still spoken today because these people still live in societies without the internet and other communication technologies! They don't even speak Spanish, their national official language, because they don't know anyone who speaks Spanish.
You don't have to know history, but try knowing a little bit more about current politics and geography before the sweeping statements?