The first 3 forces are mathematical in that they are limits imposed by the physical universe. A building can only be built so tall before it becomes exponentially more difficult to go higher. Whereas forces four through six are human-contrived. It is in our nature and our nature has evolved over millennia and therefore is not bound to change easily. Ophuls writes “It seems to take a mere ten generations for a civilization to traverse the arc from elan to decadence. Hence they tend to have a lifespan of roughly 250 years that human action can do little to extend.”
Ray Dalio confirms this statement in a recent work that parallels the conclusions Ophuls makes. In the #1 bestselling book: The Changing World Order he writes “I looked at the rises and declines of all of the major empires and their currencies over the last 500 years . . .” and concludes “From examining all these cases across empires and across time, I saw that the great empires typically lasted roughly 250 years, give or take 150 years . . .”