It doesn’t work that way with death penalty opponents, Francis.
When I lived in Utah, there was a prominent death penalty case in Utah, Gary Gilmour. This was more than 30 years ago. It attracted national attention. Gilmour admitted his guilt, he refused to appeal the death sentence; he actually wanted to be put to death.
That didn’t make any difference to death penalty opponents, they kept filing appeal after appeal on his behalf. Of course, he refused to participate in any appeals but death penalty opponents were able to prolong the execution considerably without Gilmour’s help (they would have been able to prolong it even further with his cooperation of course).
Even if somebody wants to be put to death, there will still be delays due to appeals, although obviously not as much as if the criminal is a willing participant.
Plus, you are overlooking the court challenges. Death penalty even in the form you suggest (a voluntary death penalty) will probably be ruled unconstitutional by the courts.
It doesn't work that way because there are too many loopholes and people know it.. Sympathizers and people who want justice properly will know they can still walk the street with signs and get attention..
If it was put to rest it may never go away totally but it would die down ( no pun intended )..
If you want to believe nothing will ever change it never will.. Are you sure, you're not a religious right wing person ?