Well blockchains aren't trying to solve the digital identity problem. Artists can share their public key however they like.

Then its left as an exercise for the user to actually verify the authenticity.

Sure, but if Warhol had each of his prints signed with an unforgeable signature akin to a private key, while we still have to know what is private key was, the Warhol Authentication Board wouldn't have been in the mess that it was in.

>Well blockchains aren't trying to solve the digital identity problem

They are! BrightID and Proof of Humanity are two of the leading projects working on decentralized identity. It's a pretty exciting space!

https://www.brightid.org/ https://www.proofofhumanity.id/

It seems like the digital identity problem is fundamental to actually do what NFTs claim to do, though.