A lot of people will blame conflicts on power hungry individuals, on war profiteering, or on relatively simple characterizations of cultural prejudice ("Americans hate brown people!"). There's truth in these viewpoints, but they're limited by being framed in current sociocultural issues.

It's very important to understand that there are ancient cultural feuds that people who were born and raised in the US are mostly ignorant of. For instance, India and China.

The reason that Afghanistan is such a mess internally today is that it was never a cohesive national culture in its history. The people who live there are comprised of many different cultural groups, many of whom are the descendants of various groups of invaders throughout the region's history - and as such, many of the groups hate each other due to past territorial conflicts.

Every place you might look at in the entire world, the history is like this - an endless fractal of groups trying to conquer each other, or running away from some other conquerors and getting into conflict with the locals whose land they ran away to. It goes all the way back to the time that the first hominid picked up a rock and hit another one over the head. The conflicts are so old that no one remembers how, why or when they started, but the fear and the hatred remain.

These conflicts aren't the product of modern international economic competition or ideological differences (capitalism v socialism, etc) or nationalist political division. Rather, the modern competition, differences and division exist today as an expression of the old conflicts.

To get to the world of peace that you have in mind, it would be necessary to wipe the slate of history clean.