You’re right. This is just evidence of a modern well-run supply chain.
Amazon does this better than anyone, and you’ll commonly find products available in different colors with each having a slightly different price. These prices change dynamically based on trends like historic and forecasted demand, current on hand quantities, and many other factors.
Edit to add: Some more advanced brick and mortar stores (see B&H Photo in NYC) use electronic price displays in the shelving to allow them to change prices more dynamically without incurring the labor costs of restickering and retagging product.