How does a blockchain ensure they ship the materials I requested? Did they harden the metal properly? Were the electronic parts purchased from a reliable supply chain so I don't get reclaimed ones? Did they use the right PSI steel? Did they test to known and documented quality standards, or do they ship me the ones that work, but fail quality checks that they reserve for their big customers?

I have manufactured a lot of electronic and physical products, and have had a lot of supply chain issues, but not one of them would have been solved with a blockchain.