I had a friend who was going through the program in Springfield Missouri, approximately 10 years ago, and the clinic literally increased his dose every week or two. They also had strict controls to make sure the patients actually take the full dose (because otherwise they might sell some of it on the street). So they were left with just 2 options, either drop out of the program and find their fix elsewhere, or accept a gradually increasing dose of methadone, forever. It's a sick program that is set up to make sure patients gradually descend deeper into addiction while they rake in huge profits. It's not really any different from what the drug dealers on the street are doing except that it's even more exploitative and dishonest. The doctors had zero plan for weaning people off of the methadone and some people had been on the program for years, with correspondingly huge doses doled out to them every time they came in. This was 10 years ago, at the time it cost something like $50 per visit, paid by the patient or possibly medicaid.
Edited slightly for clarity.