But still, the perpetrators here are not technically capable of pulling off a convincing forgery, so if the kids were sensitive to this issue in the first place then I guess there would indeed be no reason to insert a blockchain into the situation.
So let's take a scenario where the middle men are indeed capable of convincing forgeries: sneakers. Cardano is working on a supply chain integration there too:
https://beincrypto.com/new-balance-to-use-cardano-technology...
And my wife's students (she's a teacher) are really into their sneakers. They're also largely unaware that chain/web of trust type measures exist at all for validation of product authenticity--but if Nike started doing this, they'd become experts overnight. And then, after school, when offered a sketchy vape product, they might think twice.
Maybe that's a weak argument too. Still, I like the ability to use the same channels you money would flow through to determine if your upcoming purchase came from where you think it did, and I think that that's a capability that's going to be hard for fiat currency to mimic.
A reputable supplier of vape cartridges gains nothing from having a verified supply chain - people trust them anyway and they maintain a supply of good cartridges to protect that reputation.
A non-reputable supplier of vape cartridges doesn't care, and only sells to people who don't care what they're buying. Their lack of good reputation doesn't matter, and their lack of a verifiable supply chain won't matter either.
If the customer wants a dodgy black market vape cartridge, that's what they'll buy. If they want a quality one from a reputable source, they can already do this.