Angela,
What cavalry and chariots? Those didn't exist until long after the first PIE incursions.
Didn't they already master horseback riding by that time (and probably used horses in wars)?
BTW, I wasn't talking just about first PIE incursions, but about entire IE expansion, including Bell Beakers:
https://www.youtube.com/watch?v=hmHXBXG7Loo
And as Bicicleur wrote, they did have chariots. Which played the same role as cavalry.
As for New Guinea, refresh my recollection, do they have copper metallurgy
Probably not (because the island lacks copper ores) but what difference would it make? Probably not so great a difference.
There is some qualitative advantage, but Copper Age (Chalcolithic) weapons are not so much better than Neolithic ones.
In fact, during the Copper Age most of weapons (blades / points) were still being made of stone, wood and bone, rather than of copper.
Surely some axes (and spearpoints / arrowheads) were made of copper, but stone axes aren't so much worse than copper axes.
Tripolye cities are often considered to be rather a kind of "mega-villages" (though it all depends on how one defines a city):
Extensive trade does not count in battle, so it's irrelevant here. But they (New Guineans) have some trade for sure!
For example - the video in the OP says, that New Guinean warriors are smoking cigarettes - they surely acquired them via trade.
Is there anything similar to Tripolye culture? That's who the PIE people would have encountered, remember.
Triploye culture was just in one region - what about e.g. Megalithic cultures in Western Europe? Very different.
It depends which Native Americans we're discussing, yes?
Here some good websites (you will see many similarities with the video in the OP):
"New World Images from the 1500's":
http://www.floridahistory.com/de-bry-plates/
"DeSoto's Arkansas Trails":
http://www.floridahistory.com/arkansab.html
A Native American warrior:
Native Americans attacking a fortified town of another tribe:
"War before civilization": https://evolution-institute.org/blog/war-before-civilization/
And here some New Guineans again (war boats similar to Native American canoes):
http://translate.google.com/transla...-kto-zjadl-antropologa-michaela-rockefellera/
There's a world of difference between the Aztec and Inca Empires with their agriculture, metallurgy, cities, monuments, astrologers etc., and the more simple cultures of the Caribbean and most of North America and the Amazon etc.
The Aztecs and the Incas did have metallurgy - but it was limited to gold, or to gold and copper. They did not have bronze, IIRC. And when it comes to copper, they rather didn't use it extensively in warfare. Gold is by definition useless in warfare - they produced other gold items, but not weapons. Their weapons were not that much different than, and not that much technologically superior to, those used by New Guineans, I think. The Aztec army was certainly very well organized, but many of their neighbours didn't have such disciplined armies (which is why the Aztecs conquered them).
The score of "The Mission", by Ennio Morrione, is absolutely fabulous.
Indeed - and the last battle scene shows that those Guarani Indians were using similar weapons as New Guineans: