The answer to prison rehabilitation is purpose. While some institutions may have initiated programs to engage their residents, the feeling of a purposeful life brings a new reality to the incarcerated.
Purposes to consider will be ones that work for the incarcerated as well as the society which actually pays the bills. Special characteristics to include would be the creation of a feeling of accomplishment generated by prisoner effort and drastic cost savings for the institution.
The real loss to prisons is wasted time, no productivity and no graciousness of interactive genius. If invited, the right use of time can provide different results than now seen.
There is no profit to society when cruelness is applied to the control of citizens. There may be temporary security but that comes at a big price to the potential of all.
The best way to learn about what is possible is to listen to the troubled stories of the incarcerated people. Their genius can be tapped by mining information about how to fill the gap that they slipped in to so that newer walkers on their path can find the gap filled by their charity of sharing their pain as a love patch to the sink holes of society.
The answers through this channel are coming differently than most could conceive and that is because neither you nor I have a job whose agenda has its own needs.
You ask to imagine how much can be cut from prison costs to maintain security, improve lives, create new industry and improve the focus, flavor and flair of American life and you dowsed for an answer. You got 47% reduction and you questioned your dowsing. Your questioning is wise because there is a huge industry that has roots in the status quo.
While that is true, your answer has potential that will serve the ones that would resist the initiatives that flow from the message. Their positions are survivable as is for a time unknown but their openness to change can also serve their security.
Change will happen even if they choose to use their money to resist the inevitable avalanche of change. Their opportunities are paramount in the areas of personal safety for all and the possibility to create new meaningful arrangements that are self-sustaining for all levels of the resident base and those employed in the industry.