Modern vehicles are not designed to crush when they crash to absorb kinetic energy.?

This is actually true. The idea is to lengthen the time that the collision occurs. This sounds counteractive, but it reduces the maximum force that you feel. Theoretically, if a car can double the length of a crash, then the maximum force that people would experience would also be half. So by allowing as much of the car to crush as possible, while still protecting the passengers, makes the cars that much safer. The passenger areas are designed not to crush, for obvious reasons. Why protect a passenger throughout an entire crash to just crush them?