Wow, dramatic much? They probably sleep at night by realizing that the car they are selling you is far less likely to be its driver’s place of death than the 2003 car you’re driving.
Vehicle hacking is very real.
I'm as concerned about insecure computers in cars as the next tinfoil-wearing conspiracy theorist (that is to say- very, very much), but let's not overstate the actual numbers. A modern car getting hacked is a real risk that needs to be handled, but the actual occurrence of it in the wild is extremely low, and likely to remain that way for at least the next few decades.
So unless you're Snowden and someone is actively trying to kill you, citing the risk of hacking as a rational safety-based reason to drive a 15 year-old car just doesn't hold water.
And if you are Snowden, physically tampering with a car or just forcing you off the road is so easy, hacking probably doesn't increase the risk profile much either. Granted, it's slightly more convenient for your would-be murderers.