It's not that corporations like Nestle and Walmart adopting blockchain technology to improve efficiency in their supply chain management will increase the transparency of their supply chain to the consumer, but it could, in theory.

More likely, in the case of those large corporations which are adopting blockchain technology, they would employ a private blockchain.

Global corporations and even small businesses can utilize private blockchains, in-house, and also between other partners with whom they do business. This allows them to have proprietary information locked away from general view, while gaining the advantageous qualities of blockchain, i.e. an immutable ledger of events which can be shared between authorized parties and which removes any shred of opacity between them.

On the other hand, corporations with requirements to report information to the public, or ones that wish to do so for the benefits that such transparency would bring, are also totally capable of using a public blockchain to reveal their transactions to broader scrutiny, and thus gain a great deal of public trust.

Say a shoe manufacturer wanted to prove to the public that they don't use child labor and other terrible business practices; they could in theory, create a public blockchain, or leverage an existing one like Steem, and bring all their partners onboard, to create total transparency at every stage of production. This would also have the potential benefit of reducing margins between producer and manufacturer since the unit cost and other information would be transparent, it would create a sort of open bidding process where suppliers would have to compete among each other to provide more ethical, and more cost-effective materials... etc.

All this just off the top of my head.

The technology is neutral... it can be used for shady, or completely transparent purposes.

Steem, is completely transparent.

Yao!
@lovejoy