Putting supply chain on a blockchain isn't about verifying the authenticity of the goods. Its about being able to buy and sell the goods at any time, hedge out price risk, etc.
Can you explain this in greater detail? I don't wish to be a naysayer, but I don't understand how those concepts are blockchain-specific. Goods being re-sold/diverted while in transit was a regular occurrence prior to the existence of blockchain technologies. What is being brought to the table that is new?