The following extracts are from Daniel Quinn's book Beyond Civilization;
We weren’t the only people in ancient times to recognize the benefits of growing all our food. Among thenotable adopters of this meme in the New World were the Maya, the Olmec, the people of Teotihuacán,the Hohokam, the Anasazi, the Aztecs, and the Inca.
What’s significant for our study of this most fundamental meme is that, by the time Europeans arrived in the New World at the end of the fifteenth century, only the latest of these civilizations, the Aztec and the Incan, were still clinging to it.
He goes on to say that the others simply abandoned agriculture because they saw it as a failed social experiment. Then he claims that no explanation of the disappearance of these cultures will never be satisfactory because of the following reasons:
No such explanation will ever be satisfactory, because we all know these things:
• The soil may be depleted here, but it’s not depleted everywhere.
• Earthquakes and hurricanes don’t last forever.
• Climatic changes can be ridden out.
• Diseases run their course.
• Insect pests come and go.
• Peasant revolts can be put down—or survived.
• Invaders can be repelled—or absorbed.
It couldn’t have been things like this that made these people quit, because look at us. These things are mere inconveniences compared to whatwe’ve faced—all these things, plus much worse: famines, wars ofevery kind, inquisitions, government by torture and assassination, endlessly rising crime, corruption, tyranny, madness, revolution, genocide, racism, social injustice, mass poverty, poisoned water, polluted air, two devastating world wars, and the prospect of nuclear holocaust, biological warfare, and extinction. We faced all that and more—and never once have been tempted to abandon our civilization.
A few counter theories; As Jared Diamond points out, the crops grown in one area can move east and west but not north and south. That is why it was impossible for cultures in the Americas to expand as the whole continental landmass is mostly north to south.
Next the spread of small pox is a lot more destructive that one can imagine...to a culture that has no immunity to it. It begins fast and spreads fast. Wherever people are grouped together diseases can spread super fast and decimate a population which means that agricultural cultures are the first to go.
If we look at the dates of European explorers visiting North America we notice that Christopher Columbus arrived in 1492 and guy named Leif Ericson may have arrived a good 500 years earlier. In other words, the spread of small pox can still account for the destruction of a variety of communities. Any neighbors would be aware of any illnesses and would avoid the area maybe even the whole style of living just to avoid death by the mysterious illness.
There are various reasons for the slow development of civilization in the Americas and the theories outlined by Jared Diamond (posted about here and here) provide a better explanation than do the theories of Daniel Quinn.