There is a lot of UK talk and not nearly enough US bashing going on
We could talk about the Spanish empire, which was the biggest of its time (the 16th-17th century), spanned from America (see, I'm talking about America
) to the Philippines and large chunks of Europe, including for some time England as Philip II married Mary Tudor so for a brief spell he was king of England.
The Spanish empire slowly collapsed because it was impossible to maintain such wide-ranging dominions with the communications of the age; also, it was (very) badly managed by the Spanish crown. But bits of it lasted until the end of the 19th century, when the US declared war on Spain and we lost Cuba, the last Spanish possession in America.
"Empires" may last centuries, although their heyday may be brief. I've heard the 20th century referred to as "the American century"; I don't doubt that the US influence will still be felt worldwide for a long time, although it might be that it's starting to wane. I wouldn't know; I'm not an expert in international politics. But it does look as if China is starting to jostle for the position of "most powerful nation on earth".
And a last note on America/the US: I know it's common usage, but my pedant side gets annoyed when the two terms are used interchangeably. It's a failure of the English language not to have a word for "USA citizen" (like "Englishman" for "English person"), because the one used - "American" - is incorrect: Argentinians, Canadians, Mexicans etc. are Americans too, as the word refers to the continent. In Spanish we have a highly useful term - "estadounidense", which means "citizen of the
Estados Unidos de America (USA)". I miss such a word in English.