I also suspect he switched me to get me permanently hooked because he has seen how easily I go on and off hydro without getting dependent permanently. I hope that isn't why he did it.
I wouldn't be surprised if that was the case, but I believe that something much less sinister could be in play here. As methadone is (along with buprenorphine now days) go to opioid for opioid replacement therapy for managing addiction, your doctor could be just doing a calculation regarding FDA and his licence. If he puts you on small dose of methadone he is solving 2 problems (from his perspective) at the same time. First one being your actual pain problems and second being covering his ass. If you are on methadone he can easily justify prescribing you opioid medication at all circumstances. He can say that it was purely for pain but he can also say that he was being cautious as "he saw the first signs of addiction, so he scripted you the medicine that treats addiction and pain at the same time".
I don't believe that sales reps are pushing methadone as it is dirt cheap and basically every other opioid will yield a bigger profit. From where I sit (far, far away) it looks that he is just playing safe.
Or, if you have neuropathic pain, he actually believes in your self restraint and is giving you an opioid that is also NMDA receptor antagonist that could be more suited to your needs (pain type)...and thus having a trifecta of benefits - treats your pain, treats your pain better than opioid with no NMDA receptors antagonism and his ass is covered regarding prescribing practices.
But having wrote all that I still don't believe that methadone is answer in any case. Especially if it is not working extremely well when compared with the dose of hydro/oxycodone that you were getting before. From your opening post it is clear that it is not working that way for you.
I have met a fair share of uneducated doctors in my life and I have also met doctors that would like having a patient sicker so they can prescribe more medications. Everything is on the table and I am just speculating.
I don't know how long do you plan to take methadone on a daily basis, but as you already know (PhD in chemistry) methadone in acute dosing and methadone long term are not the same thing. You could raise your tolerance to hydrocodone (opioids in general) after just one month on methadone. That is also something to calculate into the equation.
You are a bright person and you obviously know what you are doing so I will not "preach". I am just stunned that somebody who is doing well on maximum 30mg hydrocodone is put on methadone. I hope it all turns out well and that you get the best med possible for your condition.