The people who committed crimes weren't deterred by prison sentences. Once they're released from prison, they will continue to commit crimes. Prisons don't work

The people who committed crimes weren't deterred by prison sentences. Once they're released from prison, they will continue to commit crimes. Prisons don't work. Let's put it this way - suppose someone is too illiterate to get a job (like a huge chunk of the prison population) and turns to theft to support themselves, possibly because they have a drug habit. Does locking them in prison make them any more less addicted to drugs, or any more able to get a job? Does it actually solve the underlying problem?