It's anecdotal, but all of the ex-cons I've met in Canada ended up getting stuck in a vicious circle of drug abuse after getting disappointed about their legal job prospects (around minimum wage), going back to dealing drugs a few months after probation is done and being unable to handle having an almost infinite supply of said drugs. After a couple of years of hardcore drug use there's no way someone would even hire them, so they're stuck on welfare and crime with nothing to do but getting high.