"I've never had someone steal from my car, so the fact that my car lock doesn't work is not a problem."

More like: "Every time someone stole from my car, that's because I forgot to lock the door, that the lock can be picked is not a problem".

Sure, a thief may pick your lock, but unless he knows there is something valuable in there, he will probably go find a car the owner forgot to lock, it less effort and there are plenty of them, or he may look for more valuable targets.