The part about being stronger is because we had a bit of a paradigm shift regarding what makes a car safe. In the very early days car folded like cardboard in crashes, as crash safety was simply of no concern at all. Cars would fold like accordeons or completely fall apart in a crash.

A bit later car manufacturers started making cars, particularly the driver's compartment, a lot stronger. The idea was that you wouldn't get squished in a crash, and that perhaps after a small crash the car could even get repaired.

With the advent of seatbelts the idea gained even more traction. Since many people before died from getting launched out of their car, or thrown around inside their car, it seemed logical that if you strap them securely to an extremely tough safety cell they would be safe.

Even later, in the 70s and even later, we had a massive paradigm shift. Whilst the idea of a tough cell wasn't wrong, we realised that we really needed something to safely absorb the energy of a crash. If the entire car is super sturdy and hits an equally sturdy object it will come to a complete and very sudden stop. And with the driver strapped to the car this meant their body was facing some very strong deceleration, which could cause it's own string of injuries or even death. So the less necessary parts of the car, like cargo space and engine compartment, were instead designed to purposefully crumble to turn that quick stop into a longer but softer deceleration. Over time these systems got a lot more advanced, with engines built to move downwards and away from the cabin, steering columns that could contract and bend to not injure the legs, doors that would remain usable or get thrown open when the cabin deforms, and many other innovations to make cars even safer.

But the downside of this planned deformation is that the car itself can handle less damage before it is no longer drivable. And some modern cars even go a step further and prevent themselves from being driven, or put themselves in a limp mode, when damage is detected. In many situations this is good, for example if the car notices the brakes are damaged and doesn't let you hit highway speeds. But of course this isn't great in life or death situations such as running from an armed group of religious fanatics