It's an arms race.
I used to live near a couple who were both doctors in the ER and they both drive the biggest trucks that they could find because they saw that people in large trucks tended to be fare better in accidents.
I have a small sedan for myself and a smallish SUV for my wife and kids. I feel pressure to upgrade both to something larger.
So when F150 lightning gets 5 star rating, it's within class. If you hit an overweight dumptruck you're going to have a bad time. Luckily dumptruck drivers know how to drive and that rarely happens.
However if you're in a ecobox compact, if you hit that dumptruck you're literally flat. If you hit one of the new electric vehicles which weigh in the area of 7-9000lbs. You're going to have a bad time.
If you were to properly measure safety rating not within class. It basically is just a measurement of size. So why do they do this? Clearly misrepresenting safety of smaller vehicles? It's entirely a political decision.
Bigger vehicles are more expensive. Transportation is one of the highest costs to society. So you dont want everyone driving the biggest vehicles. You want to adjust society so they choose smaller vehicles. The total cost of ownership to society is thusly less and you produce more wealth for your own people.
You can see where it's going. Private ownership of cars will remain, some people need full time access to personal transportation. However there's lots of people who really just need to be brought somewhere.
Municipalities can offer autonomous electric vehicles that say an elderly person can jump into and get to their destination much like a taxi at much lower cost than a taxi. The cost per trip is going to be measured in cents, maybe dollars with inflation? The cost of transportation to society dramatically decreases. We will be significantly wealthier.