You're missing the point.
There’s nothing wrong with capital punishment per se. Like the article says, most objectors object only because of the uncertainty of guilt.
We need to concentrate our efforts on crime detection... I propose some kind of wand with an LED on the end that turns red when pointed at a guilty person and green when a person is innocent.
I think that opens the door to gladitatorial 'running man' style TV shows, which seems like the next logical step, given we've all had a fair dose of laughing at mental patients for our Saturday evening entertainment. With the money we save not having to imprison these people, we could abolish the TV license fee while we were at it. Win win win.