The idea that any person is immutably a "criminal" is as passe as the xenophobic belief that certain ethnic groups are innately violent, untrustworthy, or simpleminded. It's a failed ideology that justifies selective dehumanization.

And conversely, how much value in contracted services performed by potentially wrongly incarcerated people performing un- or under-compensated labor are you willing to accept? If they're paying for the privilege of their own imprisonment, it should at least include rehabilitation.

I don't want to rehabilitate someone who violently murders people. If they took life cruelly, then losing the effective use of their own life is just.

In our current system, death penalty is more expensive than life in prison due to legal costs.

Random source, I believe this is well accepted though. https://deathpenaltyinfo.org/policy-issues/costs

The legal proceedings costs heavily outweigh the lifetime porridge

More than I’m willing to pay to house innocent convicts, and to pay the salaries of the people that locked them up. Fixing those problems would save a lot more money than tweaking death penalty rates (in either direction).