The factors that affect whether a visiting avatar spends money in a small shop versus a large store is similar in some aspects within virtual worlds, but also different in other ways when compared to the real world. One example of differences is the price paid for a product. Unlike the real world, large stores do not have the advantage of purchasing products in volume in which the lower price can be passed onto consumers because copyable items (or items sold through an affiliate vendor) has a near non-exist cost associated with them once the initial product is created.
However, the similarities between virtual and real world retail locations does include the square footage advantages as well as increased prim allowances which can result in a wide product offering as well as demonstration products that are rezzed more often than not. Large stores with their expansive space means that products are more likely to be sold via individual product vendors rather than a vendor with navigation arrows used to browse products like a catalog. Having more products visible at a time can also psychologically increase the chances of impulse shopping which can only benefit the bottom line.
Larger parcels also allows demonstration models to be either permanently or semi-permanantly rezzed so that the visitor can interact with and inspect the product instead of just looking at pictures or watching a video. Even though more prims are available, permanantly rezzed items tend to be the less-prim items and more of them while the semi- permanantly items will have a space set aside for them to be made available via a temporary rezzer that does not count against the static prim allotment.