Thanks for the source, it is a very good article.
The problem is I think it refutes what you are saying.
I said "saves taxes" you say no. The article says "For the "single case" perspective, then, our best estimate is that an execution saves $166 thousand in incarceration costs." Page 78 subsection C
Whether or not the person actually is executed is not germain to this argument, so don't go there. Everyone here, except you, is saying "Kill them ASAP". This equals a tax break for all of us law-abiding folks.
The jury gave them an express ticket to hell so the judicial/penal systems needs to be loading the train UP!