Not sure how you missed the point but some how you did.

The point is mechanical failures in cars happen. If it happens to something like the airbag or brakes then it’s likely not a life threatening issue.

If something happens to your wheels or suspension, your axels, etc then it can have catastrophic outcomes when you’re traveling at highway speeds.

People die all the time to mechanical failures in cars resulting in freak accidents. They happen more than you think and a lot of the time it comes down to manufacturing defects. Haven’t you ever seen fight club? The car industry is a lot more lax on safety standards then aviation is and the annual death statistics backs it up.

On the other hand mechanical failures on planes happen all the time. The reality is very few of them result in inoperability and therefore death. It would also require a series of freak incidents to fully cause a crash. Watch the show “Air Disasters” for reference. It’s virtually never just one thing or one mechanical failure that causes a catastrophic incident.