The traditional method is to just write that stipulation into a normal legal contract. That's already the payment model for some types of art, most notably acto

The traditional method is to just write that stipulation into a normal legal contract. That's already the payment model for some types of art, most notably actors getting a forever cut of backend profit on films. This tends to lead to some creative accounting whereby profit is impossible, but it's still in the contract already. No need for the contract to be on a blockchain. Nothing was stopping Jackson Pollack from writing a stipulation into the sales contracts for this painting that he gets a cut of all future resales. The only possible advantage of a blockchain here is if you don't trust the law, since the technology itself enforces a smart contract and doesn't rely upon recourse to a legal system. The downside is you have no recourse to a legal system, so if some owner of a digital good sells it off-chain (you give me cash, I give you possession of the wallet), there isn't much you can do.