My wife has a 2015 Mazda CX-5. Poor visibility out the back but it has a fair backup camera.
In May, 2018 every car was required to have a backup camera. [0] It feels like car manufacturers don't even consider visibility out the back anymore since they can rely on the camera.
For a while I drove a Jaguar, which had the leaping Jaguar hood ornament. Those were prohibited in Europe and manufacturers moved away from them. [1]
Years ago, I read that hoods were required to be higher (which blocks vision in front of the vehicle) to form a crumple zone. The idea was that a pedestrian would be tossed up in the air, land on the hood, and it would give rather than having the solid engine underneath. [2]
So there are definitely some governmental reasons why manufacturers do what they do. Thicker pillars protect passengers but reduce visibility. Etc. And most customers want bigger cars.
[0] https://www.autoinsurance.org/are-backup-cameras-required-on...
[1] https://magazine.northeast.aaa.com/daily/life/cars-trucks/au....
[2] https://usa.streetsblog.org/2017/12/07/while-other-countries...