[learc83]

>, they also have racks of goods that are stocked and sold by third parties wherein they get a cut

I'm sure that exists, but it's not common. Grocery stores often charge slotting fees, but that's not the same as renting shelf space--the store still owns the product (even if there is an agreement to buy it back if it doesn't sell).

Also retail stores take on more product liability than marketplaces like flea markets do.