Distributors add value to a supply chain between a supply stage and a customer stage
if there is a small number of customers requiring a large amount of product.
if there is a large number of customers requiring a large amount of product.

if there are many small players at the customer stage, each requiring a small amount of the
product at a time.
if there are a few large players at the customer stage, each requiring a large amount of the
product at a time.