Correct.
I went through high school and college before 1968, so what I was taught about the penal system was that the purpose was to rehabilitate criminals. Once they "paid their debt to society" they were supposed to be suitable for reintegration into said society. Today, of course, prison doesn't make any pretense of rehabilitating anyone. Many states have outsources their prisons to for-profit jailers whose only concern is maximizing profit. Prisons have become training academies for thieves, and recruiting stations for gangs. I have difficulty perceiving the new model as an improvement.
Prison cannot rehabilitate anyone. In some cases, they can offer programs to help an inmate rehabilitate
himself, if he is indeed committed to change. The State of Ohio has numerous programs aimed at rehabilitation. Most are a waste of resources as inmates use them merely as a way to check off a box at a parole hearing, pass the time, or give them access to other (hopefully gullible) people who they can try to manipulate into doing something for them. Some people do not need a program to keep them from coming back to prison- some make reckless mistakes they will not repeat, others recognize it as a dead end and become productive citizens.
Prisons have always been places where criminals train and recruit one another to some extent. I don't know how the recidivism rate from 50 years ago compares to today, like most stats, they can be easily manipulated. I would observe that a couple things have changed over the years.
First, like much of the rest of society, generally criminal's attitudes have changed. The entitlement attitude is very prevalent- they don't think they did anything wrong to get locked up, they certainly don't believe they have a debt to repay to society.
Secondly, in the past, prison was not really a place that most people wanted to return to, so there was some deterrent effect. Today, prison is extremely soft. The philosophy seems to be that keeping the inmates happy and entertained will allow a prison to run smoothly. Along the same line, disciplinary tools to hold inmates accountable for bad behavior have been greatly impeded. For example, segregation units are limited to a few privileges that can be denied an inmate, even then, housing them there for more than 6 days is considered "torture". Inmates have no incentive to behave. They have no consequences if they do not behave. As a result, the inmates are much more inclined to do as they please, which equates to more violence, gang activity, etc. The appeasement policy has led to prison administration having less control of facilities, not more. They may prefer to not be in prison, but if the experience is no big deal, they have again disincentivized changing one's criminal behavior.
I have 29 years in corrections and have seen many changes- few of them for the good.