Walmart is famous for its existing supply-chain and logistics management system (that tracks numerous international parties and middlemen in any given transaction) and is notorious for using that system as one of its cudgels against suppliers who displease it or who it wants to beat up on regarding price.
Put another way, they already keep a very close eye on everything that goes into and out of their stores from point of origin all the way to customer returns and have done so for decades. Adding a blockchain ledger doesn’t add much value to what these heavy-handed control freaks already have.
