On the subject of back window wipers, half of my last 16 cars were saloons, which non of them had a back wiper, but I must say, I missed not having the opportunity to give my back window an occasional window wipe and wash in bad weather. Even on the other half that did, I only occasionally used them, but was still glad to have them. I will no doubt miss having one on my next car a Hyundai Ioniq 6 which looks to me as if it would have benefited from one, but having a 360 camera will be a help.
The only saloon I can remember off the top of my head as having a back window wiper was the 90’s Peugeot 308 saloon, which I thought was great, but unfortunately not enough to actually buy one.