Darkness is the norm

Copper production shows three peaks: The Roman Empire in the west, the Song Dynasty, and modernity.

The Roman Empire in the west and the Song Dynasty had about seven times the preceding and following level of copper production, thus while those civilizations were going concerns, they had far more production and wealth than the rest of the world put together.

When the Roman Empire in the West fell, its GDP dropped about a hundred fold.

So, looking at the past few thousand years, the norm has been relatively brief periods of civilization in relatively small parts of the world.

I would guess the problem is that the state lacks the cohesion and self discipline necessary to refrain from devouring civil society, and anarchy lacks the cohesion necessary to keep the roads safe and property rights secure. Technology can advance during anarchic periods, often quite rapidly, but the amount of wealth, as indicated by copper production, shipwrecks, and such, tends to be very low indeed during such periods.  Despotic states, on the other hand, have higher wealth, probably because they can make the roads safe over a large area, but are apt to end technological progress, and often reverse it.

Technologically, Somalia is probably the most capable state polity nationality in southern Africa, while Botswana was remarkably prosperous for a black state, when ruled by a combination of traditional monarchy and DeBeers, very thinly disguised as democracy. Singapore trembles towards crisis and decline as its pretense of democracy shows dangerous symptoms of becoming real.

In America, it becomes impossible to do high technology in physical things without an ever multiplying number of permits, which require paying off an ever multiplying number of bagmenconsultants. This exploding regulatory state resembles the decline of the Song Dynasty, where all high technology became a state monopoly, all education aimed at state jobs.

In Rome, the decline of military discipline, for example the year of six emperors, meant that the legions became more like mobile bandits than stationary bandits, though even to the very end of the Roman empire in the west, Roman handouts to an ever more degenerate underclass, the infamous bread and circuses, remained startlingly generous. Rome taxed beyond the Laffer maximum, so Diocletian decided that if high taxes discouraged people from working, the state would make them work.

Our ever increasing underclass has become a problem like the legions, where the state in every election promises goodies far beyond what it can actually deliver. The underclass is a lot easier to shaft than the legions, yet the Roman Empire in the West, still making a thin pretense that the Republic lived, failed to shaft its underclass, until the fall of Rome.