But you mention the concept of commission also which I know distribution agencies does take commission and buckle the channels to operators.
Take Example of FMCG products. Suppose P&G launches 5 items and price them differently as A, B, C, D E
But they don't sell its products directly and appoints a distributor and gives him a some commission ( which he saves from distributing himself) . Now a distributor is market knowledgable and analytical person. He prepares his Sales presention what buyers expect
And so product reaches to end users. This is how it works.