I'm just as good as the most accomplished artist at reading numbers from /dev/random, that's why I don't see why one random-looking string would be more valuable than the other.
That depends on who thought of making the NFT first. Which isn't necessarily the artist.
> or its proven to have been generated by a person who exclusively had a certain private key
That has the same problem, it's generated by arbitrary pseudo-random numbers, rather than a real, living human hand. Look, I'm not disputing the underlying cryptographic principles. I'm happy they exist, because they are immensely useful for many purposes, like securing communication and financial transactions. I just struggle to see the artistic merit in someone having pulled some numbers out of /dev/random and having done some math on them.
I am not sure what you mean by this. Are you referring to art being duplicated, or a digital signature? You can verify that its a forgery, or from a different account than the first author. The digital signature isnt something you can replicate. You can print another one, but you cant duplicate the property of "first" itself.