Does anyone know why on earth Audi didnt fit a rear wiper ?

What a bizarre thing to leave out. Did Audi ever offer it as an option or is their a retrofit kit ?

Even my my early 1980's Ford Capri has a rear wash wipe, very useful on the occasional long journey, not that it gets driven in bad weather much. Seems daft in the A7 that to do the same I have to pull over and find a rag to wipe the rear screen.