[fauigerzigerk]

>Large retailers have this exact role: they certainly demand and get lower prices from their suppliers. We need a non-profit version of this

This was tried a lot in the 20th century (starting in the 19th century), usually emerging from the labour movement. I think in food retail and energy it has mostly failed or simply stopped making a difference. The profit margins of food retailers are small to begin with and easily lost by being a bit less efficient.

But Europe and the UK in particular has been using a similar model pretty successfully to keep drug prices low. Some argue that costs were merely shifted over to the U.S. I think this is only partially true.