European colonization of the Americas greatly set back human progress

I’m often not great at staying focused while listening to audiobooks and was bored silly with the first hour of 1491: New Revelations of the Americas Before Columbus, by Charles C. Mann. But I really wanted to know more about his challenge to the long-held notion that the Americas were a sparsely populated wilderness before Christopher Columbus landed ashore. 

Luckily the Hoopla library app has a 20-page Cliff notes-type summary. Here are my Cliff notes to the Cliff notes. Caution: it's interesting stuff:

• As the last Ice Age receded, the New England region turned into an ecologically diverse landscape. Many people were hunter-nomads, but there were also settled villages with established agricultural practices.
• As early as 1616, hepatitis began attacking the indigenous population in the region. It had been brought by European settlers and killed off most of the region’s native Americans. The same thing was happening in Peru. The sophisticated engineering and military capabilities of the Inca society were no match for the smallpox brought by Europeans. Hernando de Soto’s exploration left almost no population in its wake in the Mississippi Valley, thanks mainly to the diseases his pigs carried.
• Europeans understood how diseases operated and spread, but there were not any attempts to halt or slow colonization. Transmission was often viewed simply as God’s will. Scholars have put the death totals in the millions, suggesting there had been a significant population in the Americas. 
• The human die off truly set humanity back, as there was a ton of knowledge and advancement lost in the entire colonization process.
• Peru’s mountainous landscape was shaped by continental drift that became an attractive locale for diverse groups of Indians around 10,000 B.C., with complex societies, governments, and urban centers common by 3200 B.C.
• The cultivation of maze throughout Mesoamerica was truly one of humanity's greatest feats of genetic engineering. Native American ecological influence could have helped greatly advance society's progress, but Europeans wiped out the native people and, with them, almost all their knowledge of landscape architecture and the urban settlement of places like Cahokia, Illinois, near modern-day St. Louis. 
• I grew up very close to Cahokia, where several mounds/hills still exist. It’s amazing to think back to how advanced this society was in 1250 B.C. before it collapsed around 1350 due to environmental mismanagement, social unrest, and a devastating earthquake. Likewise, the Mayan population collapsed between 800 and 830 B.C. because of overpopulation, resource overuse, and severe drought. 

Mann’s conclusion is that the Americas were not an untouched wilderness but rather a complex environment that worked because of the interplay between humans and natural forces. This suggests that people now and in the future should focus on building sustainable habitats rather than trying to simply reproduce what has been done in the past in terms of restoring ecosystems.