It all started in Le Mans many years ago… In the past, a race would start with all cars lined on one side of the main straight and the drivers lined across the opposite side.
At the starter signal, everyone would rush across the pavement, enter the cars, start the engines, engage first gear and hopefully start the race unscathed. Did you notice that I didn’t mention seatbelts ?
In these conditions being able to start the engine and engage gear at the same time could save you a few precious tenths… Hence the smart move by Porsche to relocate the key / starter button opposite the gearlever side.
However, this finished in 1970. Safety concerns (all those guys running across the track…) and the universal adoption of seatbelts meant that a standing or rolling start became mandatory. But the tradition lived on…
Today, all Porsches (Cayennes too !) still have the ignition key on the left side, for LHD cars, or right side for RHD. Perfect for bragging rights at the pub !