They could shut out all 3rd party sellers until they are verified. Amazon would still be making truck loads of money from Amazon basics etc. Most customers might not even notice any change when buying.

Verifying is useless if you aren't also tracking inventory provenance, which Amazon can't do while also being able to compete in their own market, as they would have absolutely no way to argue they weren't operating on the basis of privileged access to third-party information via analyzing specific inventory granularity sales flow.

That's the issue Amazon absolutely does not want to happen. Getting locked out of their own marketplace or aggregated sales data would hugely undermine the value proposition in terms of de facto earning and profit taking potential, while at the same time undermining public faith in the overall market.

Amazon can't admit they can do anything about counterfeits because no one in their right mind wants to contribute to a platform that empowers and informs a potential competitor.

This is becoming what I consider velvet glove business combat 101 that no one openly admits to.

This discussion is becoming circular. Please revert to my initial comment for my reply to this one.