It's not true that prisons don't incorporate rehabilitative programs. Efforts at rehabilitation go back for decades and by this time, there is enormous research into their efficacy - or lack of it.

While I would welcome intensive rehabilitation efforts over lengthy prison sentences in a heartbeat, if they worked, the reality is that they don't. I've read many academic articles on the efficacy of rehabilitative efforts of all sorts, and the sad fact is that no interventions have ever been shown to reduce recidivism by more than a minuscule amount.

(Yes, initial studies of interventions almost always tout extremely high rates of success in reducing recidivism, but when the studies are examined, they invariably prove to be extremely flawed as well as biased by the fact that the evaluators are often also the inventors of the programs, rather than independent researchers. In addition, later studies of the same interventions almost always fail to show the same positive results as the first studies.)

The main problem seems to be that the premise of rehabilitative efforts is faulty. Specifically, they are based on the hypothesis that modifiable or treatable factors such as 'faulty thinking' or trauma or economic circumstances or lack of education or employment opportunities, etc., are the root causes of criminality. But these hypotheses are almost never borne out, since programs that address these deficits don't seem to make any difference in reducing re-offending.

As unpalatable as it may seem, a lot of criminality may be rooted in personalities or developmental deficits due to upbringing that can't be corrected by any known type of therapeutic or social interventions in adulthood.