>>935903989 (OP)Globalism is a thing because we all get richer if we trade with each other. Throughout history, trade has always brought prosperity to those who partook in it. Nowadays, modern economics explains that even if country A can produce two goods for cheaper than country B, A is better off specializing in one good and trading to B for the other. This is the law of Comparative Advantage.
In addition, technology has made the world “smaller”. It is faster, cheaper, and safer to ship goods or travel, and near instantaneous to communicate with people in what were once distant lands.
Another factor touched on already is security. The U.S.-led rules-based international order is seen by most countries as mutually beneficial for everyone. One big reason is that U.S. maritime might (and that of her allies) mean that shipping routes are protected from piracy and acts of war. Institutions like the United Nations have also played a role in this Pax Americana—the American-led peace that has obtained since the second World War.