“There is no instance of a country having benefited from prolonged warfare.”
Sustained conflict drains both sides; the winner merely loses less, so end things on your terms fast.
Chapter 2’s thesis, stated as a historical audit: there is no instance of a country having benefited from prolonged warfare. Sun Tzu has counted the costs — silver, weapons, ardour, solvency — and now delivers the finding. The verse is deliberately absolute, because its audience is the ruler contemplating a long war in the comfortable belief that victory launders duration. It never has.
A partnership dispute enters its third year of litigation. Both sides’ counsel describe the eventual victory in glowing terms; neither deducts the years of management attention, frozen deals, and legal burn that the "winner" also pays. The companies that thrived were the two that settled in month four on imperfect terms — both walked away lighter and whole, which no verdict would have made them.
Read alone, the verse sounds like pacifism. In context it is arithmetic: duration is the destroyer, so the skilled strategist either wins fast or declines the long game entirely — including declining the temptation of a slow war of attrition that "we can afford better than they can." Sun Tzu’s reply is already in the verse: nobody affords it.