I recently noticed that the elevator at my favorite cinema has been out of order for weeks now. The less mobile patrons need that elevator to transport them downward to this underground theater. I then learned of America's "elevator crisis" and my mind wandered to the struggle to maintain the Roman Empire. I'll explain the connection below. But first a refresher on Rome's predicament:
The Roman emperor Trajan brought the Roman Empire to its greatest extent during his reign (98 to 117 A.D.) with his successful conquests in what we today would call the Middle East. Rome's many conquests had been financed by booty taken from the conquered.
But its hold on the sprawling empire—one that reached from northern England to southern Egypt, from Spain in the west to what today is called Iraq in the east—would henceforth have to be financed by rising taxes and inflated currency. The money was needed to pay for armies and naval forces to defend the empire's very long land and maritime borders. Building an empire turned out to be less expensive than maintaining one, including building and maintaining the infrastructure of roads and military and political outposts needed to protect and administer it.
What happened to Rome's maintenance bill happens in any system of infrastructure as it expands. The existing infrastructure must be maintained even as new infrastructure is built. Eventually, it becomes very expensive 1) to pay collectively for maintenance of all existing infrastructure and 2) to pay for increasingly aging infrastructure that requires extra expense.