You know if you skip too many oil changes, it's going to cause long-term damage to your car, so why would you skip network maintenance?
Think about how most businesses handle their vehicles. You don't wait for the engine to seize up on the highway before you decide to look under the hood. You handle the oil changes, you check the brakes, and you rotate the tires. You do it because a broken-down van means missed deliveries, angry customers, and a massive, unexpected repair bill.
Yet, when it comes to technology, so many businesses run the engine until it literally smokes.