I'm forced to ask what felons are doing on the street and why they're not in prison.
Of course, if you consider felons to include non-violent drug offenders then of course the thing to do is decriminalize drugs so the criminal black-market in drugs and gang warfare will go away. Then it will cost neither $400k or $30k. It will free up hundreds of thousands of prison cells in which to put violent criminals like murderers, rapists, and child molesters.
As for "non-violent drug offenders?" Non-violent perhaps. But that does not mean their behavior is cost free. Burglary, larceny, car theft, theft of CD receivers, wheels,etc. All ads up. In the hundreds of millions of dollars. Much of it to support their drug habits. Cocaine/Meth,Crack, etc. very expensive. I too would be homeless if I had to spend thousands a month to support my drug habit. Consequently, many turn to drug dealing, theft, prostitution,etc. Drugs are hardly "victimless."
I'll agree that many NON-violent offenders do not merit incarceration, tax offenders come to mind. Pot farmers with 6 plants? Hardly merit concern. Efforts should be focused on VIOLENT offenders. 70% of cops are killed by people who cannot legally possess firearms in the first place, i.e. felons. They are everywhere!