All very sweet, until you come across the cold, hard fact that people are not inherently good. Some are actively good; by far the majority are morally neutral but socially and legally compliant; finally, there are those who are actively evil.
Not a popular word, 'evil', one that has sadly gone out of use in some places. But the simple fact is that there always have been, are and always will be, some people who are going to steal or cheat rather than work. There will always be those who use physical force and fear to get what they want from others, rather than work for it. There will always be those who torture, maim and kill others because they enjoy it or simply because they can.
No matter how much you improve the lot of ordinary people, there will still be thieves, fraudsters, conmen and gangsters. Even a Utopian society would still have them. Because in any society there will always be some things that require effort to achieve, and thus there will always be those who, rather than make an effort, will simply take the fruit of others' work for themselves. No amount of equality, equity, training or empathy will change them.
As to the killers and so on, they are so distorted that even an attempt at treatment is useless.
As long as there are people, there will be criminals, and as long as there are criminals, we will need police and courts to deal with them. I agree that prison doesn't work. I agree that social and economic changes will greatly reduce the number of criminal actions. But there will still be the hard core of 'bad to the bone' individuals who won't change. The answer is euthanasia.