It doesn't matter whether he was sentenced to death, nor does it matter that he didn't spend enough time in jail to get to his actual execution. The point is that the man was innocent, and, since he's not dead, is now able to pick up the pieces of his life. Had they executed him he wouldn't be able to.
It matters a great deal. You offer you anecdotal claim as evidence that the death penalty is bad because innocent people will be executed. Yet you anecdote demonstrates no danger of that at all. Because the case was weak, the death penalty was not sought, nor had enough appeals passed that an actual DP case would have neared execution.
Your anecdote serves to refute, not support, your position.
Complete privatization. Now don't ask me exactly how that would look, but competition in justice would be better than giving a monopoly to an unaccountable organization.
I'm a Rothbard, Laissez Faire Libertarian. But few things terrify me more than for profit prisons.