This doesn't require a middleman, even pre-blockchain. Proof of Ownership of digital content has existed for at least 30 years; digital signatures were a featu

This doesn't require a middleman, even pre-blockchain. Proof of Ownership of digital content has existed for at least 30 years; digital signatures were a feature of PGP. I could host the original video (original quality before upload) on my own website, link to / host my PGP public key, host the content digital signature on my website, then post these links in the YouTube description after I upload it there. NFTs don't always identify the owner publicly by their real world identity; typically the blockchain only proves that a particular wallet id owns the content. Hence, there is another link in the chain to be proven for your use case. PGP doesn't necessarily fix this either; it only proves that the digital key pair own the content, not an IRL identity.