Because of the way that the animals are kept is my guess. When you're a small time breeder or just a hobbyist, you generally tend to have fewer snakes and may keep them with hides because the expense at that number of snakes isn't that high, and if you're a hobbyist or small time breeder, you may also tend to handle the snakes on a whim because you don't have as many so would have more time to spend handling them.

Larger scale breeders have tons of snakes so they 1. would rather spend the money they'd save on hides for something more useful and 2. have their snakes solely as breeders, in small and generally dark tubs, and they don't take them out and handle them unnecessarily, so the snakes really aren't disturbed very much and therefore wouldn't need the hides as much.