This is definitely not uniform. I worked on inventory management at Target, and stores had quite a lot of shelf space—to the point where we'd hold large amounts of cheap, non-perishable stuff like cat litter because, well, we had the space for it.

Stores also wanted to look full. We actually had parameters in our inventory management logic to increase inventory just for presentation reasons. If inventory is expensive, having some free, quality inventory can be valuable in and of itself even if it moves slowly.