Is it the last frontier or basically already full except for mountains and jungles?
Are they eager for immigrants to build the interior, or wantint to export their teeming urban masses?
This is one big, complex economic and social question that colleges teach over several Latin American Studies courses. They have the land and resources to be an area with an number of parameters. However, South America has not been stable economically, militarily, or socially in its post-European history. Argentina was fairly prosperous until fairly recently and Brazil has a world-class economy but things just haven’t fallen into place to make it an area where large numbers of people would want to immigrate.
Asia and India “support” that many people only in the sense that the ground doesn’t collapse under their feet.
The overpopulation is immediately clear and quite devestating. Even in major cities basic infrastructure like electricity, water and sewage is severly lacking and at times non-existant. Just outside the city centers there are slums with no permanent there are slums with no permanent buildings, much less sanitation facilities, that streach for miles. There is just no way to successfully support that many people, especially on a third world budget. And it can be next to impossible to get people to stay in the countryside living out your rural visions- they all want to be in the city where there are jobs and where one bad season won’t actually directly kill them.
In other words, more population doesn’t lead to more prosperity. Usually it just leads to more poor. South America is most likely focusing on keeping it’s population under control and improving the economy through increasing business.
Compare the slums of South America to the slums of Mumbai.
Short answer: You haven’t raised the bar very high.
You’d be hard pressed to argue that the land masses of India, China or Indonesia very well “support” their roughly 2.5 billion inhabitants. Of course, the term “support” is so debatable as to render your question almost unanswerable, at least within GQ’s parameters.