Or it’s just cheaper to build
Those pillars that hold the roof up are safer if they're sturdy, but sturdy means wider and that obstructs the driver's field of vision a bit, and weighs more. "strong and slender" is possible, but it costs more. It all inter-relates.
(strong, narrow, cheap), pick any 2.
There does come a point where you start to appreciate what Polestar is doing on one of next years models (the Polestar 4): give up on the idea and change direction; no rear window at all, just a camera.
And I'm not only thinking about damaged camera. Humidity, weather etc. often makes these cameras completely useless.
You'd have to have wipers for your camera-lens and probably heating or something as well to even approach the utility of a window - short term.
Because none of that is ever going to fail, and it isn't cheap either.
It is IMHO a bold move, which will attract fans and haters. Neither of us know for sure how it will play out; if the potential issues outweigh the rest. The implementation details clearly matter. In a couple of years we will see if it's a genius innovation, a terrible misstep or somewhere in-between. Until the vehicle ships and is on the road for some time in some volume, we won't know for sure.
After all, on a high-end vehicle a back-camera that hasn't sorted this is just a gimmick.
Maybe they have, all my experiences indicate otherwise though I don't have much experience with new expensive cars.
You don't see lots of truck parking in parallel unassisted on streets with pedestrians and cyclists, but I do this all the time.
Reminds me of the 18 wheeler at the traffic light. He got red while waiting for his left turn and decided to back up instead of "going for it" once oncoming traffic had seized.
The minivan behind him got crushed like it was made of sticks. Luckily he heard the noise after a while and stopped backing up. Not a pretty sight. I had the side view so I was like "WTF is he doing?" when he started backing up. Well he couldn't the minivan who had snuck up behind him.
Lesson: when behind a truck make sure you can see the drivers face through his mirrors. Then you have a chance that he is going to see you. If you can't see his face, assume that he can't see you. Move away.