This is a ridiculous take. First, doctors don't get paid a commission for prescribing medications. Doctors don't get a commission on the medications they prescribe. They get the same money from your office visit if they tell you to pursue diet and exercise or if they write you a dozen scripts. Only if you go doctor shopping will you get a doctor who gives you whatever you're looking for -- they're out there, and they usually run TRT clinics or do Brazilian butt lifts on an assembly line.
The only arrangement that would even make sense would be a pharmaceutical company bribing a doctor for the promise of prescriptions. However, there are severe flaws in that thought process. First, the money in prescriptions predominately goes to pharmacy benefit managers and insurance companies. Not doctors, not pharmacies, and increasingly not even the manufacturers. The people getting rich are the ones who push paper, not pills. Second, while this kind of bribery has happened in the past and I'm sure it's gonna happen in the future, we now have something called Prescription Drug Monitoring Programs, which are national or regional databases that track who prescribes, fills, and consumes controlled substances. Between that governmental oversight and the shifting policies in practice groups, it's much harder to both dispense and receive potentially dangerous medications for conditions where they're not indicated. Third -- and this is massively important -- the ADHD medications that comprise over 95% of the prescriptions for ADHD are in generic. Adderall, Concerta, Focalin, Vyvanse, Ritalin, and so on. There's no "big pharma" entity there to be handing out piles of cash. There's a shortage of ADHD meds because there's not a ton of money in supplying them anymore. That's the exact same reason there's a shortage of insulin and many opiate formulations.
There's not even enough money in fulfilling the demand, much less greasing the palm of one doctor at a time, all 200,000+ primary care/family medicine docs in the country.