I don't think a system that's focussed on rehabilitation rather than punishment would be popular with American voters.
Countries that do focus on rehabilitation in western democracies, often hand out less long sentences and treat their prisoners relatively nicely. Their own cell, tv, etc. Still prison though, being robbed of your freedom is punishment in and of itself. On average that leads to better outcomes, lower recidivism, ....
But on a case by case basis, discovering someone who committed a heinous crime was let out after 10 years? Sure, often monitored, evaluated, and with stringent conditions. Sure, only if the chance they'll do it again is very low. But still. It doesn't feel right. Same thing with nice prison cells. Show the average American a Norwegian prison cell, and tell them it houses a rapist, and they'll be understandably offended. Think it isn't fair. Which it almost certainly isn't, but you don't lower the chance of repeat offending by sticking someone in a cage for ten years.
Also, I do wonder if these kinds of prisons are possible in a country without a semi-decent social safety net. If jail's better than being homeless, and homelessness is rampant, people will commit crimes just to escape. You end up rewarding criminals, because jail is comparatively nice compared to their existence outside jail.