Nothing. This is a canard, though, because the fundamental nature of blockchain technology allows a potential buyer (or anyone, really) to verify the provenance

Nothing. This is a canard, though, because the fundamental nature of blockchain technology allows a potential buyer (or anyone, really) to verify the provenance of an NFT. It's then up to the buyer to verify that the NFT originated in a wallet or account associated directly with the artist. As a buyer, as always, it's your job to verify that you're not buying a counterfeit. As a seller, as always, the value of the NFT you hold is subject to its verifiable provenance.