Right, this is a maintenance program the same way a seboxone or a methadone program is a maintenance program. The goal is to minimize withdrawal and eventually wean the addict off of the drug, which is accomplished through the tandem use of maintenance program and therapy.
Opiates nor benzos nor alcohol nor any of the more commonly abused drugs were intended for long term use. The physical deterioration that occurs is just too great in long term use, addiction aside.
Also, synthetic opiates like hydrocodone and oxydodone are legal. People still rob pharmacies to get them, and people still purchase them on the street. Legalization does not stop illegal activity associated with substance abuse, obviously. Anyone who thinks it does is simply naive.