A complex system that works is invariably found to have evolved from a simple system

See A complex system that works is invariably found to have evolved from a simple system

A complex system that works is invariably found to have evolved from a simple system that worked. A complex system designed from scratch never works and cannot be patched up to make it work. You have to start over with a working simple system.
— John Gall, Systemantics: How Systems Really Work and How They Fail