Safety, and aerodynamics (i.e. energy efficiency).

Dismissing it as "design with poor usability" is very facile. It's trade-offs between different goals, all the way down.

Or it’s just cheaper to build

Cost is yet another trade-off.

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.

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.

The failure mode is pretty horrible though.

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.

Lens washdown is rather common now on vehicles.

I don't think that I said that the Polestar 4's lack of rear windows is a slam-dunk sure-fire hit. Rather just that we can appreciate the attempt to side-step the issues with rear-window visibility with a very different design.

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.

While I agree I kind of think this should be nailed down before such a departure.

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.

Trucks drive just fine with no rear view at all other than side mirrors, so cars can do that as well.

Truck drivers are pros, though, while we're just annoying traffic jam fodder.

They can't see what they can't see. Being a pro makes no difference.

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.

On the highway, sure. But generally whenever I see a truck back up in the city, there will be someone outside directing the driver.

You don't see lots of truck parking in parallel unassisted on streets with pedestrians and cyclists, but I do this all the time.

Hmm? They specifically taught me in driving school how to parallel park using just the side mirrors.

Americans don't care about the prices of their cars and neither do American safety regulations.

This is correct. It's easy credit all the way down. Cheap cars (Chevy Spark, Mitsubishi Mirage, Kia Rio) are basically all slowly being discontinued in NA, meanwhile luxury pickups sell like hot cakes.

It's safety. Same with thicker pillars which are worse for visibility but made thicker for rollover protection.