Could a pharmacy run out of common items more often than rare ones?
Popularity creates pressure.
Yes. Common products often face greater demand variability. Even large inventories can be depleted quickly when many customers need the same item simultaneously.
Many people assume rare products are the most likely to disappear. Demand often creates the opposite outcome.
The hidden mechanism is concentration risk. A product purchased by many customers experiences more unpredictable spikes than a niche product with stable demand.
Imagine two products. One sells a few units every week. Another sells hundreds but occasionally experiences sudden surges. The popular product may create shortages despite larger inventory levels.
A second-order effect develops when customers anticipate shortages and begin purchasing earlier or in larger quantities, amplifying demand further.
People often think shortages reflect scarcity. Many shortages reflect popularity.
