Part of why this is a problem is because car companies compete with each other on safety. And a good way to do that is to add more mass to your vehicle so that in a car crash your own maintains more momentum and therefore imparts less of a deceleration on you than a smaller car would. So the end result is a arms race between car companies to build bigger and bigger vehicles (and also less fuel efficient ignoring ICE improvements in recent years).
Compare that to airplanes where instead of competing for safety, they all cooperate on safety. The end result being that all planes are safe and rarely crash. Granted, airplanes are inherently at lower risk than cars due to their being less of them and them being separated by large distances in the sky. But in the end cooperation vs competition of safety makes a big difference in everyone's safety as a whole.
Airplanes are also only operated by trained professionals who are listening to other trained professionals for coordination. Driver's licenses are given out like candy.
The solution is obvious, just tax the SHIT out of heavy vehicles. 100€/y for every 100 kg over 1000 kg. 2.5 ton death machine? That'll be 1500 €/y. 1.7 ton BMW ? 700 €/year. Seems fair to me.
Problem is consumer tastes and automotive lobbying makes this totally politically untenable.
Taking a plane is a service that people buy. Making flying dangerous makes people less likely to buy flights.
For a car, the operator either owns the vehicle or is known by the owner. It gets used differently, and there is an accepted lesser standard of safety.