Population density was extremely low, almost laughable by today's standards.
Since always there were as much population as the combination of each land and culture could sustain. Never forget that. People starved periodically and how to deal with it, both intra-culture and externally was something everyone who left descendants was forced to manage quite well.
When I have compared with others our heritage -same one or different- I always jokingly said "I descend from those who took the right decision". I mean, I descend from a lineage of an average of about 150 generations of farmers, hence, they periodically faced famine and had to take the decision of eating the seed for the next harvest -in low technological contexts the ratio between crops and seeds is as low as 4 to 7- or letting one or two of their children starve to death. They did the last, consistently, hard as it always was, or did any tricky action they needed to do to avoid the first, so I'm here. That means, my life is sort of a privilege of a high cost, and I always think about the future and analyse present decisions in the light of future consequences, all for a good reason.
That treat make me similar to Bolivians from the Highlands. We're completely different to Bolivians from the Lowlands and Paraguayans: they are descendants of hunter-gatherers with a little horticulture. They are used to make the most of the present. Every of us has a little of that, for instance, when some people eat cookie after cookie until the tray or box is empty, then they find they're no longer hungry. These peoples more focused in the shorter terms are much dependent on chiefs and big kahunas to take the long term decisions. They are fiercely loyal to their chiefs. That's one of the reasons why democracies in Latin America, Africa and South East and West Asia tend to tumble: they are much dependent on hetmans, so they are easy victims of demagogues.
I had the great opportunity of having a crew of Paraguayan labourers working for me. It was a great experience, and how both them and me learnt how to deal with each other in the most constructive way. Of course, I had to do the most of adaptation, but I came to love and respect them, to never let them down, and I learnt a lot of things including how to cease the day and look at it with good eyes. Call it racial interchange, ethnic interchange, cultural interchange or whatever you want. It only can be enlightening.