You're forgetting that these hackers cannot do this to any car (specifically the Jeep, since it's the only one that was remotely hacked) off of the lot.
They heavily modified the code, even went through 2-3 ECU's before they got it right, to do what they did. The hackers would have to swap ECU's in your vehicle first in order to take control, or plug directly into the OBDII port (and be inside your car with you).
The fear mongering by the media is strong with this story.
If you're talking about just flat out stealing it, then
any car with keyless start is vulnerable, all the way up to Ferrari, Lamborghini, etc.