This does require facilitating the implementer to have full access to use the original product.
People get around this via "clean room" reverse engineering where one engineer tears down the thing to be cloned and writes a detailed spec, and then a different engineer (who has never seen the internals of the thing in question, and so isn't "tainted" by that knowledge) implements it from that spec. You could do this with AI, but then all that spec writing/reading is done by a machine too, so you haven't really bought yourself anything legally.
To be clear, I'm not a lawyer. I'm just musing aloud.
This means they no longer hold copyright on their code.
My point above is just that this ("ChatGPT, make me a clone of Paint Shop Pro 4 but for modern Linux and in Rust. Here's a copy of the executable to get you started.") is a much more straightforward, old-fashioned kind of copyright infringement. I don't see why a court would treat it as different from "Let me decompile paintshoppro.exe to an IR and then recompile the IR for a Linux."