How many bloody times?
It's easy: don't put these sort of systems in places they don't belong.
The vast majority of car journeys contain only the driver, who has exactly no need of a wireless internet within the car. Of the rare occasions where passengers are carried, how often will said passengers require the use of a device which does not of itself have internet connectivity?
Start making cars which are transport devices and not mobile hotspots. And start that by restricting the essential operational and security functions to their own private wired networks.
Biting the hand that feeds IT
