With the right product a company can go from nothing to several million in sales - just through catalogs. You compete more easily. Catalogs offer a level playing field for the big corporation and the smallest start-up. With few exceptions, products are judged and sell on their merits, not on the reputation or size of the manufacturer. You need just one product.
Catalogs evaluate one product at a time.
So the one-product company is not at a disadvantage as they are when trying to break into a department store. You save on packaging. So you don't need an expensive 4-color box. In fact, the simpler the packaging the better. A plastic bag is often sufficient.