I've seen this "ancient systems" idea go by a few times. Honest question: If these platforms are so old, they likely aren't terribly complex, from the perspecti

I've seen this "ancient systems" idea go by a few times. Honest question: If these platforms are so old, they likely aren't terribly complex, from the perspective of what's now computationally cheap. So, how hard would it be to drop a computer on their local network and just dumb-clone the whole thing?