When I was growing up in the 90s with 2 siblings we had a small hatch. When I had my second child we had to upgrade from a small hatch to an SUV because we simply couldn't fit a car seat behind the driver. Even now, I'm not sure if a third would fit.
Sure, the SUV itself and the extra padding on the car seats might make my children safe in collisions with other big cars, but if we were all still driving hatches then maybe none of that would be necessary.
We are in the stupidest arms race.