I completely disagree that it is too time consuming and expensive to teach the OW class so the student understands and can demonstrate buoyancy control, proper finning technique and correct weighting and trim.The people that I have helped get trim and buoyancy, with a 1 on 1 and a whole dived dedicated to it, you get 'close'. You don't get spot on because the 'student' still had a lot to learn about being calm, not over finning and waving the hands around, and easier breathing. To do that with every student would be time consuming, therefor end up being expensive.
Unfortunately too much of the model in these parts is to almost give away the class, not an outright loss leader in some cases, and make money on the materials and equipment.
Instructors must want to teach. I don't see they can possibly make money, and I consider their exposure to risk to be not trivial. Kudos to them, I wouldn't do it. It's plenty to host dives for the club.
Your point on the "model" is correct, however the fuse is in the box, that model is over.