There was not any shortage at the manufacturers. Toilet paper, like many other commodities, has a stable demand for its different types and varieties. 60% of all toilet paper is made on dedicated machines for residential use, and another 40% is made on different dedicated machines for commercial use. The machines are not convertable. Residential TP is multiply, softer, and on traditional sized rolls. Commercial TP is single ply, and on very large rolls.
The manufacturing output and demand is relatively stable year after year. The shortage came because the demand for commercial TP dropped and the redidential TP demand soared. SInce the machines could not be converted from residential to commercial, the manufacturers were only able to go 24/7 instead of 12hours for 5 days.
Similar issues persist for foods. Bananas, for instance. The largest bananas are shipped in bunches to the stores, but the less desireable smaller bananas are removed from the banana stalk one by one and sent to schools for student lunches. Since the schools were closed, the bananas were left to rot in landfills.
Many foods are shipped to restaurants, but rarely purchased for use in the home. Salad greens, olives, garbonzo beans, baby corn are just a few examples. They were still produced, but sent to landfills, uneaten.