The term 'prosumer' has taken on a number of slightly different meanings over time. I'm using it as Alvin Toffler intended when he first coined the term in his book The Third Wave (1980) to describe a blend of producer and consumer.
He envisaged a time in the future when consumers would play a part in both the design and manufacture of products, so they could be made to individual specifications. Consumers would therefore become a part of the creative process rather than passive recipients of the goods that industry supplied. This could create many micro-markets where the line between producer and consumer is blurred so there is no room for the middlemen.
The availability and affordability of production tools (like cameras, design software, printers and 3D printers and so on) and the breaking down of traditional distribution networks (via the internet and consumer-generated courier traffic) is creating an expectation amongst consumers that they can have a say in what shapes their lives.