Also, libertarianism USES human greed as a positive force for advancement and change. Innovation. You get to keep what you EARN, but try and steal anything and your victim just may kill you and be morally right to do so.
BIG behavioral modifier there, that whole "death" thing. Zero recidivism rate.
You have only theory, and Heinlein fiction. No proof.
The only problem with that is it assumes that the person getting killed is the one attempting to steal.
If you take away the stigma of the law and its consequences,which you would do if there was no government,how do you know that someone today who would not steal would be tempted to,knowing that he can get away with it if he kills you first.