The lack of empathy here is just astounding. People commit crimes because they seem like the best course of action. They are either desperate, ignorant, or imbalanced. If you actually want to reduce crime, you'll find that education is cheaper than incarceration. Incarceration just piles all these people together to make an environment that perpetuates the criminal behavior.
Instead, there's too much money to be made in prisons now. Also, criminalizing people makes them easier to control.