> The iPhone has to reliably connect for emergency calls and provide accurate location.

An iPhone handling an emergency call is an exceptional use case.

A car driving is not an exceptional use case for a car.

A life and death scenario is occurs every few minutes, or continuously for something like a mountain road, if something like brakes, limited throttle, or steering were to fail.

But, I would, naively, assume that the operation of these critical components were in no way related to timing requirements of some process in Linux.