A toilet paper factory has a long planning cycle and supply contracts, so it cannot react very fast to large changes in demand. The machinery also costs a lot, so they cannot increase the capacity for every spike in demand that will usually disappear in a few weeks. The weakest chain is the Wall Street pressure on these companies to "improve cash flow or else" that lead to reducing the stocks (product and raw materials alike) to minimum, so any surge is even harder to compensate. I worked in this area for some years, this is how it's done.