Countries, empires, and civilizations with cost diseases eventually choke on their own inefficiencies.
Cost diseases did it for Rome and the Ottomans. And India during the Mogul era (allowing easy conquest by England). And they are to blame for the “century of shame” when China became so dysfunctional that foreigners bullied them unmercifully (which China is now determined to exact revenge for).
There are various theories as to what causes cost diseases to take hold of stable countries and empires.