There's a lot missing from the diagram... everything before the ends of a transaction.
90% of a possible transaction's value chain comes from intermediaries.. and they can't appear in the diagram which only considers the ending.
Unlike the internet, there is quite a bit of value in the middle of the network... my friends help me to decide which manufacturers have value, and evaluate their reputations. The Government prevents me from making transactions that are harmful to myself or society. Marketing folks help me learn of the existence of things I might want.
The relationship formed after an actual purchase is only a small part of the picture, it's time to look outside the box.