Stop lying. No major commercial insurer is currently lobbying Congress for limiting the number of physicians. In fact, some insurers have even voluntarily donated to support residency programs (although the amounts are small relative to Medicare funding).
OK, I now tend to believe that when the ACA capped the profit margins of insurers, their previous incentive to reduce cost of care (so they could keep the savings as profit) ended, so they stopped lobbying for restrictions on the supply of doctors. Unless I see evidence to the contrary, I will continue to tend to believe that large employers (not subject to any cap on their own profit margins) continue to lobby for restrictions.
I tend to believe this because of how strong the correlation has been in my own "career" as a patient between my ease of access to doctors' time and how much my insurance plan ends up paying for tests and treatments.
Limiting doctor availability is an effective way to limit total cost because most expensive health care goods and services require a doctor to order or prescribe the good or service. I.e, until the patient gets enough time with a doctor for the doctor to realize that the good or service is necessary (then prescribe or order it) the insurer does not need to pay for the good or service.
Limiting the supply of doctors will increase costs in the long run because it reduces access to preventive care. Residency caps disproportionately impact PCPs.
It might reduce the costs they pay for preventive care or non-urgent care, but serious issues will progress.
You might not have to pay for metformin to treat diabetes, but you’ll eventually end up paying for a hospital stay and amputation.
Your proposed incentive for insurance companies to want to restrict the supply of doctors (prior to the ACA) doesn’t make sense, and that’s what I’m trying to convince you of.
Nope, there are no major self-funded employers lobbying for physician caps either. But hey, don't let facts get in the way of your ridiculous, uninformed beliefs.