Methadone is a "coping" drug for heroin addicts, but the problem is that methadone ends up being just as addictive. Maybe in a different way (I don't know all the physiological explanations) but the point is, you end up with addicts that just get addicted to a prescription instead of heroin.
The article is misleading when it suggests that prescription drug enforcement is being ignored. I worked tons of pill cases when I was in narcotics. There's a black market for them just like everything else.