The most simple and straightforward answer is that most of the richest and most powerful nations in the world have a 4 season climate with cold winters and warm to hot summers. This means that they have a much shorter growing season than places where the climate is less varied over the course of a year. In warmer climates, food can be grown year-round, and vegetation doesn't die in the wintertime, so not only can people continue to farm, they can avail themselves of things that grow naturally and uncultivated such as berries and other types of fruit, nuts and grains, etc. Because the people living in harsher climates had to make due with a much shorter growing season, they had to make changes to their society. If you want to live through a cold winter where you won't have access to the food you normally harvest and your supply of wild game will be severely diminished because many animals hibernate or migrate in the winter, you've got to take steps to assure that you've got a sufficient supply of food stocked. That's much easier to do if people work together and agree to store their food communally and divide the stocked food out piecemeal. But in warmer climates, people don't need to ration food - or if they do, it's for a different reason such as when the dry season comes for example, so they don't need to subsist for anywhere near as long as people do in colder climates. They had less incentive to work together and it wasn't as necessary to gear their society toward cultivation. The effects of this are still evident today. Children in Western countries such as The United Kingdom and the United States begin the school year in September. This is a holdover from the days where children were expected to help out on the family farm. But because people in warmer countries didn't have a particular time of the year to harvest, they very sensibly begin their school year when the year actually begins in January or February.
When the growing season is short, there's bound to be competition. Europe is not a very large place by world standards. And the amount of arable land is rather small. The areas where enough food can be grown to support a sizable population have been fought over for centuries. To look at modern Europe and to identify the success stories one would never suspect that in the past, the richest European countries were by far the most poor. Scandinavia was a backwater. Why? Because it lies in Northern Europe and it was difficult to grow enough food in a land of steep mountains and boggy soil where the frost sets in early. That was one of the driving factors in the Viking Expansion to other - to more desirable, parts of Europe. There simply wasn't enough arable land to go around so people had to emigrate. In these modern times, countries that can't grow enough food can buy it from other countries, or they can grow it in greenhouses using technology, so that doesn't matter.
People living in more temperate zones didn't need to be as competitive. Why fight if conditions are all the same everywhere? You have plenty of land to grow food and to gather edible plants and so do I, so I don't feel compelled to fight you to try to seize your land. With no competition, there was very little fighting, so people didn't focus on the mechanics of war. They didn't dedicate a lot of time and money and effort to military power the way they did in Europe. Europeans have been fighting each other and killing each other for centuries. In the parts of Europe where there are few geographical land-forms delineating the boundary between one society and the other, wars have always raged. The vast European steppe has been a path for the invader since the dawn of man's presence in Europe. But things are different in warmer climates. Often societies were separated by dense jungle, by sprawling deserts, or they were simply spread out on a chain of islands some distance apart where they weren't forced to live shoulder to shoulder. While the situation in Europe certainly led to a lot of fighting, it also lent itself well to cultural diffusion where new ideas and new technologies could spread easily from one society to the others. That wasn't the case in warmer climates.
There are many countries that are located in relatively warm parts of the world that are wealthy, but for the most part, they are wealthy because they became wealthy in modern times or because they were heavily influenced by Old World societies where a 4 season climate exists. Brazil, Mexico and Argentina are the richest countries in Latin America. All three were once colonies of a European power. Australia is located in the Southern Hemisphere and was once part of Britain. Singapore is a very wealthy country - its economy is based on its strategic location and its financial industry, it too was once a British colony. Some of the nations of the Middle East are extremely wealthy because they have vast reserves of oil, but that didn't mean anything hundreds of years ago when there were no engines to fuel or factories where pieces of machinery required oil to operate. Those countries became rich when they possessed a commodity that the rest of the world needed.
So what you have is a situation where people living in a 4 season climate were predisposed to be more competitive, more warlike and more innovative and people living in countries without harsh cold conditions were not particularly compelled to compete with one another, go to war with one another or be innovative. Once these two groups of people finally met, it's completely obvious why Europeans were able to dominate people from other parts of the world.