Maybe we should start with something easy and clone Nethack by just playing it through..

Astra Max can do 12%: https://balrogai.com/

Though after improving the harness it can fare better, but still no completion: https://roger-creus.github.io/blog/astra-craftax-nethack/

In general I agree, but in the context of this specific thread what you're saying is a mathematical impossibility. Now could you use pure observation to get the gist of a game and maybe even have AI fill in the rest with fun new details? Yes. And what you'd end up with is an approximation of the game missing some things and adding others, not a clone of it. But you can't use pure observation to form a complete solution of a game when there are more possible game states to enumerate than there are Planck times left until the heat death of the universe.