Question: What were they trying to achieve with the 2005 version of the ignition switch, which required a new design, that couldn't be provided from a 1975 switch design? It seems that a lot of effort and money is poured into redesigning every component of products every few years, when this was a solved problem many decades ago. After all, the ignition switch has to 1) be turned with an authorized key, 2) provide electrical contact for accessory, run, and start positions.
Have you had a car made in the last 15 or so years?
Nowadays ignition switches do everything but starting the ignition system. As the car is fully controlled by a computer, the key is an electronic gizmo that authenticates the driver as the owner and signals the starting sequence. The revolving movement is completely unnecessary and just provided for familiarity purposes, there are cars that instead of a key have a card and start by pushing a button.
My bet is that maybe in 2005 GM was building the first switches under this principle, thus the need to preserve the electrical characteristics of the system, so the data transmision channels between the key and the computer wouldn't get compromised.
Ah, that explains it -- my F150 pickup truck is 14 years old, the only technology it has is an RFID chip in the key (which I assume is read by a sensor in the location of the ignition switch, fed to the engine computer, but otherwise not requiring any other re-design of the key switch).
A 1975 switch probably doesn't have the same crash characteristics as a modern one, it's quite common that keys in older cars will penetrate your knee during a crash.
