Just because a thief would find themselves driving the car on public roads in the state described doesn't mean that the owner would actually do the same. It's

Just because a thief would find themselves driving the car on public roads in the state described doesn't mean that the owner would actually do the same. It's amusing that the car is lacking in security features, but that doesn't make it easy to steal. It's funny that it's hard enough to drive that a previous thief gave up and (essentially) gave it back. The biggest hint is in a caption: "I’ll make sure the drivetrain is in the car, by the way." He's obviously working on the car to try to make it better, and there's no way he's actually going to put the drivetrain back in the car just in case someone wants to try stealing it.