The post treats thermodynamics as a picture of street fighting turned into law. Joseph Tainter's The Collapse of Complex Societies (Cambridge, 1988) treats it as an energy bill.
Societies solve problems by adding complexity: more ranks, more specialists, more army. That works, then each extra layer of order costs more than the last. When the next increment returns less than it costs, collapse is not a sermon. Local groups stop paying for a hierarchy that no longer pays them. Tainter's other two cases are the Classic Maya and Chaco Canyon. The long case is the Western Roman Empire.
Rome ran on this year's sun. Tainter, following A.H.M. Jones (The Later Roman Empire, 1964), puts about ninety percent of government revenue on agricultural tax. Conquest paid once: annexing Pergamon in 130 BC doubled the budget; Pompey's Syria added about seventy percent; Caesar's Gaul dropped the value of gold in Rome by about a third. Then you garrison forever. In the third-century crisis (235–284) the state met wars and usurpers by growing the army and the tax machine. Tainter's line is that the West survived that century by eating its capital — productive land and peasants — and then could not afford to be the Empire.
The grain system is the pipe. The Oxford Classical Dictionary's entry on the annona: Rome at about a million people, tax grain from Sicily, Sardinia, Africa, and from Augustus onward Egypt, run by a praefectus annonae. When Constantine's new capital took the Egyptian grain, the West leaned on Africa. When the Vandals took Africa in 429, that western supply ended.
That is not a subway vigilante. It is a state that still claimed the right to say which force was allowed, and ran out of surplus to keep the claim.
Those are two different ways the converter can fail.
The post's failure is an inversion of the rules: harsh on people who intervene, lax on predators. Switzerland versus a handful of American cities. Who may use force, and who later says it was allowed.
Tainter's failure is the energy cost of the architecture itself. The rules can stay clear. The hierarchy still becomes a worse deal than walking away. Late-imperial peasants who stop resisting invaders because the tax is already taking the surplus are not confused about self-defense law. They are leaving a costly club.
They disagree on what to watch. If the post is right, a polity with a predictable after-the-fact audit of force and ordinary people still allowed to defend should hold even as the surplus thins. If Tainter is right, that same polity can still come apart when the next increment of courts, garrisons, and grain ships costs more than the order it buys.
A split you can score without a new country: the Vandal cut of 429. Grain off, western supply ended, while the legal claim to monopolize legitimate force was still on the books. If order tracks the audit, cutting the grain should not by itself dissolve the cities. If order tracks the surplus, it should. Tainter is betting the second. The post, as written, has no row for that.
The post already prices the machine. Section V says a hyper-centralized attempt to make private force physically impossible is expensive and brittle — the gardener stops, the plants die. Section VII says a parasitic monopoly can trap energy in defensive overhead with no drop in actual threat. I was treating "thermodynamics" as if that bill were missing.
What is still open is which bill. The post's bill is the inversion: you pay for security you do not get, and you are forbidden to supply it. Tainter's bill is the complexity curve: you can have a fair audit of force and still be on the wrong side of diminishing returns. Rome is the case that would decide whether those are the same sentence.