Notice how empires rise and fall all the time? It seems to be the nature of the paradigm (footnote 1). All of those big, thick history books recognize it: The Rise and Fall of the Roman Empire, The Rise and Fall of the Third Reich... The rise and fall of Western Civilization? It could happen.
The empire builders never learn, however. The sun never sets on the British Empire. Right. Alexander the Great conquered the world and died early after which his empire crumbled. The pharaohs built empires and where are they now? All wrapped up in linen and buried in the sand unless they've been dug up by archaeologists. Pizzarro took the Roman Catholic priests with him to justify genocide of the Incas' empire. Together they stole the Incas' gold, raped the women and children, and then, if the Incas wouldn't convert to the Spanish version of Christianity, they were slaughtered mercilessly. The Spanish were particularly bloody empire builders.
In modern history, WWI broke up a whole mess of empires. The world had been divided up, by more or less mutual consent, by the Brits, the Spanish, the Portugese, the Germans, and even the Dutch. All abused, plundered, and exploited their colonies. Few colonies rebelled sucessfully (footnote 2). The imperialists were just too powerful militarily for the "undeveloped" countries.
The Treaty of Versailles (footnote 3) punished Germany for its arrogance, rearranged all the empires, and created conditions for the emergence of new ones. Within 20 years after the War to End Wars, Germany, Italy, and Japan went after the established British, Dutch, and French empires. (footnote 4) The result? World War II.
After that, the Western European empires collapsed, although the Allies tried mightily to reestablish them. The new threat of the Soviet Union and Communism distracted the already weakened imperialists. The Dutch lost Indonesia. The French couldn't hold Indochina and passed it off to the United States, who stupidly accepted the burden. The Brits lost India and the Middle East. The Belgians and Portugese lost their holdings in Africa. The world was a disorganized mess. The "Third World" was up for grabs. But all that was left from WWII was the U.S. (Democracy) and the U.S.S.R. (Communism). That battle went on for the next 50 years with Democracy emerging victorious. Maybe.
Democracy is the latest empire. And we're making the world safe for Democracy. Not to mention safe for the dollar.
Prediction: WWIV will be fought with sticks and stones.
Further reading: anything by George Orwell