I think their still being incarcerated is symbolic. It’s probably the most well-known case out there; it was horrific and that kind of extreme, random violence was not common at the time. Just like it’s pretty clear that Manson is a schizophrenic but he’s not going to be released to a mental health facility anytime soon, those people will most-likely die of old-age in jail.
I tend to agree that just because a prisoner has reformed, doesn’t mean s/he shouldn’t suffer the consequences of what s/he’s done (victims’ families may still be suffering). But I also agree that there needs to be some sort of reform and move toward rehabilitation: Input from victims’ families on parole/release, reassignment to a more appropriate facility if the person becomes infirm or aged, treatment and appropriate incarceration for those with mental illness. I’m not too familiar with the prison system, but I know that there’s too many people in jail and that it costs a lot of money to keep them there when they’re too old to hurt anyone anymore.
Also, if we’re not going to bother to rehabilitate folks when they’re in prison, we shouldn’t release them back into the world with the same attitudes/lifestyle/resources/skills they had when they went in. I does neither the general population nor them any good. It’s one thing to reform oneself in jail, but does that reform stay with prisoners when they leave and have to deal with the pressures of the outside world? I wonder if there’s any research on the success rate of released prisoners.
Not an organized answer, apologies up front.