You're not wrong. The basic pattern that has been repeatedly demonstrated across the historical record of a powerful polity that well meets it's peoples' needs arises, and then gradually decays as corruption eats it from the inside out until it collapses amidst degeneracy, corruption, and treachery and people manage to replace it (which I can't recall a single good example of) or it's conquered from without by a new, up and coming polity. This basic pattern has been ongoing since the dawn of history and the advent of Sumer, conquered by Akkad, and so forth. A very short read (25 pages), John Bagot Glubb's 'The Fate of Empires and the Search for Survival' well illustrates the author's conclusion that such imperial polities have a lifespan of ~250 years. Rome nearly doubled that, but the Republic was replaced with the Empire, and that is why it lingered longer. Perhaps that's an example of people replacing their collapsing polity from within? I'm not a very good student of history, so can't really trust my ill informed judgment.
Anyway, the USA is 249 years old. So, there's that.
Thanks!
we are overdue...