Could we ever switch to this or any of the many other rational systems? Unlikely: tradition is difficult to overcome.

What makes something simple or complex? It's not the number of dials or controls or how many features it has: It is whether the person using the device has a good conceptual model of how it operates.

adults forget how difficult that task was.

Any time you see signs or labels added to a device, it is an indication of bad design: a simple lock should not require instructions.