Seems to me it is you who keeps repeating yourself. The point is not to pretend to foretell an actually undetermined future that depends entirely on us, but to make it.
When someone, or a group makes the same mistake that others in the past have done, a person can predict to a high probablity what the general outcome will be.
For example, when you continue to spend more than you can afford, you will eventually go bankrupt.
And all unsustainable trends eventually reverse. Whoopie doo. Doesn't have anything to do with the fall of Rome, or the next 100 years of US life.