The author misses one key point: it’s not only about debt coming due on their scheduled dates. It’s that much of this debt is also saddled with covenants that can cause a debt to be collectible at any time if the terms are not met. Things like a company's loan-to-value ratio, leveraged inventory through high accounts payable, and other financial metrics. In short, market troubles can force long-term lines of credit to abruptly come due.