They weren't the only ones to "win" they just happen to be the winners in our historical moment and in the context of our culture. Other civilizations did go pillage and conquer. Europe did it to themselves first. We just happen to be living in the moment where we all consider it the most important and consequential outcome. If humanity continues under capitalism, there will be many more and someday someone will wonder why the US won in the 20th century if not for them reacting to the dust bowl.

It's not that Europe was uniquely equipped to be imperialist, it's that they're the biggest and most recent example (other than the US) that we're familiar with. Also what makes them unique is European Industrial Capitalism, of which we're the living most immediate result. Mayans didn't have industrial capitalism. Neither did China or Japan. None of them even had capitalism.

Every society in history has their own contradictions. Every moment in history has a dominant contradiction. We're used to analyzing the contradictions of capitalism, and that is indeed what Marx wrote about. So to understand European history in pre-capitalist times, you have to look the contradictions of the time which may or may not be the same as under capitalism. England vs France is a contradiction. Monarchy vs Subject. Lord vs Serf. These things drive what happened.

Contradiction 1: Humans vs environment. Humans depend on the environment and yet we alter it when we gather resources for production. If you cut down most of the forests in the UK, for example, this contradiction comes to the forefront of those who depend on lumber. Whether it's a business, an artisan, a merchant, a monarchy that needs boats, or a peasant that needs a house.

Contradiction 2: Monarchy vs Subject. The monarchy needs its subjects for production and defense and legitimacy. If subjects are overexploited, they revolt, and this becomes the dominant contradiction.

Contradiction 3 to infinity: Monarchy vs Monarchy. Monarchies fight over territory and whatever ways that expresses itself in the culture (ie honor, religion, etc). At some point the two can no longer afford to keep fighting over a boarder that isn't moving. There is no one left to conquer. So you have to develop the cultural idea of a treaty or truce. Then you team up and go conquer new territory because that may come with wealth that the other kingdom doesn't have.

These contradictions are the underlying cause and which one specifically depends on the moment in history and the society in which the contradiction exists.

It's important to stress that even peaceful societies have contradictions. They are unavoidable as they are the result of existence. Even indigenous societies had contradictions and they were also resolved by war. Even a perfectly communist society will have contradictions, it's just that we will have resolved the contradictions of capitalism specifically.