wow thats a huge reply!
I think I'd benefit from a shared common database where I could source all the products I need from one place. You would benefit from a shared common database but it does not need to be decentralized in that case.
And allow me, and my suppliers, to better negotiate the supply chain and help reduce costs.
Sure you can negotiate with your suppliers to reduce costs, but tell me which suplier would like to make his all deals public? I dont know such supplier, deals 100% must be private, so other buyers wont see your deal details such as amount discount etc.
Also i don't know how 'small' is your business, but here in my small european country i see a lot organic food producers who handle everythig very well.