I'm no expert, but I'm very sure that the difficulty in finding items in a retail store is by design.

If every customer walked in, grabbed exactly what they needed without looking at anything else, paid and left, the stores would probably make half as much money. It's common knowledge that "big brand" items in a grocery store go on the eye-level shelves because the distributors have paid more, and I remember reading that the ends of the aisles ("caps" maybe?) are super-primo real estate - that's why the ends always have Pepsi and Tostitos and big-name items. It's probably the same reason there are "impulse items" in the aisle when you check out. Oh, hey, yeah, I do need some gum, why not buy a pack.