Re: The worth
There is the reputation cost to the manufacturer.
If your car is listed as easy to hack, if your car is vulnerable to an attack that could potentially give the attacker control of the car, then you have to do something about it.
Re-engineering your product will be expensive - as they said, it is not easy to bolt on security, it should be built into the design from the start.
Recalling "defective" products will be equally, if not more, expensive.
It doesn't matter that the hack is unlikely, or that only a psychopath would try to crash cars. If there is a public perception that your cars are unsafe then your reputation will be adversely affected.
(It doesn't affect Android, or Windows, as much because people don't see vulnerabilities as the fault of the OS, it's the fault of "bad people". It's a different matter if it's your car the bad people might be hacking.)