You're not going to be able to sell a forged baseball card at Christie's. You can't prove its provenance, and it wouldn't hold up under scrutiny.
NFTs aren't scarce. Anyone can make them for anything. I can sell you the couch I'm sitting on as an NFT.
If I own a Picasso, I could burn it, have my tigers urinate on it, or make sure no other human ever sees it again. I can do whatever I want. What exactly can I do with Jack Dorsey's first tweet? Get him to delete it? Change it into an ad?
There's no legal framework behind NFTs. Ownership is meaningless. If you bought my couch as an NFT, good luck coming to get it.
Also, when the cryptography behind NFTs is broken (and it will be!), what happens to the ownership? If the chain switches algorithms, not everyone will update their keys. After breaking the old scheme, ownership will instantly be impossible to prove.