re: Why are distributors needed?

I work for a pet product manufacturer. The amount of distributors has drastically decreased in the past 10 years. Most of it is due to consolidation, big box stores (PetSmart and Petco) and online sales such as Amazon that we sell direct to. Good distributors are still valuable for us because they go into the independent stores and detail shelves, etc. But the good ones seem to get bought up pretty quickly.