The end conclusion seems to be, yes, people in PNG (or wherever) are our equals, and if only they had wheat/horses/small pox instead of potatoes/llamas/syphilis, they’d be running the world economy now instead of us.
I believe that this is almost a correct view - but only if all of the differences in technology and cultivation are taken into account, and if it is instead put further back in time (as in, it would have been people from PNG or the Americas who would have controlled the world economy for a few hundred years after contact). In order to show why this is something of a straw man, however, here are some of the other differences involved between Eurasia and the Americas.
Smallpox was certainly important, and horses - yes, very powerful animals. These definitely gave Cortes and Pizarro an advantage against their American opponents. Wheat is perhaps less exciting (just another grain, really!). But think about what other technologies Europeans had that pre-Columbian South Americans didn't: Sails; compasses; swords; guns; crossbows; chain-mail; metal armour; light, fast ships designed for the open sea; writing (the khipu isn't really all that close, even in the most generous interpretations); map-making; even fire-making with flint and a steel striker. And then add in all the diseases Eurasians had that Americans didn't (in addition to smallpox, perhaps the biggest killer): measles, flu, bubonic plague, pneumonic plague. And then add all of the other domesticates Europeans used or ate (animals and plants): chickens, pigs, sheep, goats, cows (several species), wheat, barley, rice, rye, parsnips, turnips, millet, etc. Many of these had uses beyond their nutritional value - especially cattle, of course, but also sheep for their wool. American camelids could only serve some of these functions.
Consider where each of these things had come from. The compass was invented in China, as was gunpowder, although it may have been Central Asians who were responsible for the first guns (as opposed to bombs). The sail was ancient in Eurasia, whereas it didn't exist even in the Caribbean, America's closest analogue to the Mediterranean - let alone the lateen sail that gave literal impetus to Magellan and Columbus (and which was probably, but not definitely, an invention of the ancient Mediterranean [it was also independently invented in the Indo-Pacific]). Crossbows came originally from southeast Asia via China and the Arab world (perhaps). Writing - or at least, the Latin script that we use - has an ultimate origin in Egypt via Canaan, Greece, and Italy (again showing the importance of diversity in the rise of Eurasian, or indeed, human, technologies). (It is notable that before the European conquests, scripts derived from Egyptian precedents were used throughout Europe, North Africa, and South, Central, and Southeast Asia, including the Latin, Mongolian, Nagari, Kawi, Baybayin, Cyrillic, and Siddham scripts.)
Chain mail was invented in (probably Celtic-speaking) Europe in the first millennium BCE, with lamellar armour invented in several locations (and plate armour a later innovation allowed for by the development of sophisticated steel-working technologies in the Arab caliphates). Ships designed for the open sea had been around in Eurasia since before the first millennium BCE, while they were much later developments, often post-Columbian, in the Americas (although some Caribbean canoes were reasonably large and stable). Cartography was also old in Eurasia, with surviving Chinese, Arab, Greek, Roman, and Byzantine examples, whether copies or originals, from the first millennium BCE.
Smallpox came from the Sahel and became the incredibly deadly disease it used to be in India, before propagating itself successfully throughout both Africa and Eurasia through contacts brought with trade and conquest. Influenza and several forms of plague grew from the Eurasia habit of keeping close contact with animals and living in cities. The sixth century CE Syrian plague would have been impossible in the Americas because of the late development of urbanisation and high population density, and the absence of pastoral economies outside of the Andean cordillera. Each of these Eurasian plagues was spread by trade and conquest. An Asian strain of bubonic plague entered Europe in the wake of the Mongol conquests, via Crimea. No such conquests ever brought the Americas together in this way, largely because of the extremely limited contacts between South, Central, and North America.
Cows were probably domesticated in north Africa. Horses were domesticated on the Eurasian steppe in the fifth/fourth millennium BCE, far outside of the main centres of 'civilisation' (again, diversity, both ecological and cultural!). Chickens were domesticated in India and reached Europe by the fifth century BCE. Pigs were domesticated in several locations, including China and the Near East. Rice was first cultivated along the Chang Jiang valley in what is now China and had been introduced to Italy by Ludovico Sforza before Columbus sailed, and both wheat and barley were barely differentiated from their Near Eastern ancestors (due primarily to the fact that the climate of the Mediterranean and European Atlantic coast is relatively, although not absolutely, constant). Rye was grown in colder environments than wheat could be. Maize, by contrast, had to be specifically adapted and selectively engineered by Americans to enable it to survive in more northerly environments - and this meant that, for populations new to agriculture, maize was slower to take hold. It had probably only been grown in Ontario, for instance, since the sixth century CE. Other American cultigens, including manioc and sweet potatoes, were tropical plants that could only be grown within a thin band of the earth's surface.
So consider this: if Europeans had visited Peru in the fifteenth century with no horses, no wheat, and no smallpox, but with every other advantage they had; and if the Peruvians had possessed horses, wheat, and smallpox, but not any of the other European innovations, then perhaps the Europeans would have been wiped out by the smallpox, or at least badly infected. Perhaps that would have led to an epidemic in Eurasia and millions of people would have died, as had happened hundreds of times before in the history of the continent. But what could the Peruvians have done in the interim? Sailed to Europe to take advantage? Hardly - no such technologies existed in the Americas to allow this. And no tradition of cartography, in the navigation sense, was present, either, let alone a tradition that spoke of a spherical earth that could be sailed around. They would not have been able to capitalise on the victory.
Eurasia's astonishingly diverse but interconnected human history led to the sharing of innovations of several sorts that provided Eurasians with an almost automatic technological advantage. Europe's proximity to the Americas and the desire to directly control the trade in spices through maritime exploration and conquest resulted in Europeans being the first people to introduce Eurasian diseases to a human population that had been separated from them since the Pleistocene. The destruction that resulted enabled the greedy, genocidal, and poorly-organised European forces to plunder the immense wealth of the two continents. This started the flow of wealth to Europe that resulted in booming economies and massive militaries, enabling Europeans to fight unprofitable wars if need be.
Now, that doesn't entirely explain inequality today. We could over-rule all of this history and work out a way to create a more equal world. But this history is the root of global inequality. It is the reason Europeans were able to conquer the earth and consolidate their position - and it is at least partly the reason for Europe's continued economic success. It is the basic, central answer to the question of why it is that Europeans, or 'white' people, are, or rather have been, the prestige group of earth with a disproportionate share in its resources.