Let me guess, you've never worked in a real production environment?
When your software supports 8, 9, 10 or more zeroes of revenue, "trash the old and create new" are just about the scariest words you can say. There's people relying on this code that you've never even heard of.
Really good post about why AI is a poor fit in software environments where nobody even knows the full requirements: https://www.linkedin.com/pulse/production-telemetry-spec-sur...