The reason we know more about South and Central American civilizations than those of North America is:
a) Limited archaeological evidence in North America
Compared to South and Central America, where there are notable archaeological sites like Machu Picchu or the Maya ruins, North America has fewer large, well-preserved ancient cities and monuments. This limited archaeological evidence in North America contributes to our relatively lesser understanding of its ancient civilizations. It's not necessarily due to the sophistication of the civilizations or a lack of interest but more related to the nature of the archaeological record.