My experiences with Medicare and my supplemental insurance policy have been very good. Here's an example. Last year I had 3 stents put in 3 heart arteries. Two separate operating room procedures and 10 days in the hospital. The first day was in Intensive Care. On the last day I was discharged at 6 PM so I only spent 9 nights in the hospital. With cardio rehab and numerous doctor's visits for various things the entire financial trail took 8 months to run its course. Just for fun I tabulated all the expenses and what was paid.
Total List Price For Everything - $364,581.93
Total Amount Paid by Medicare A & B - $27,589.59
Total Amount Paid by BC-BS Plan F - $3,553.84
Total Amount Paid by Me - Zero
Of course I've been paying for Medicare B and Blue Cross - Blue Shield of Arizona Plan F and BC-BS AZ Value PDP drug plan so it wasn't really zero cost, but it didn't cost me anything more than what I've been paying for my healthcare insurance. This year (2022) I've been paying $170.10 for Medicare B, $197.07 for BS-BS AZ Plan F and $36.20 for BC-BS AZ Value PDP drug plan each month. So $400 a month for all my health insurance needs. The drug plan has a deductible and copay but they aren't enough to justify the added expense of the next level drug plan.
I don't have dental insurance or any kind of optical insurance. My teeth are in good shape so that's not a big expense. I've had one crown replacement in the last 10 years. Other than that it's been the usual biannual dentist visits for cleaning, x-rays, etc.
Medicare covers eye doctor exams and probably most procedures, but I haven't needed to have anything done so I can't say this for certain. If I want the eye exam prescription it's an extra $45 payment to my eye doctor. I don't get it unless I'm planning to buy some glasses in the near future. I only use glasses for reading, working on PC, etc. In the last 22 years since having LASIK done I've probably saved enough on glasses to pay for a good percentage of the LASIK procedure. ($4,400 in 2000)
The only thing I've had done in the last four years that Medicare wouldn't pay for was a Cardiac Calcium Test that measures the calcium buildup in your heart arteries. It was $104 which I was happy to pay since my cardiac doctor thought it was a good idea. My score came back as nearly zero. Turns out the CCT test doesn't detect plaque and plaque is usually what causes heart artery obstructions. Seven months after having the CCT I needed 3 stents, which gives you an idea of what the CCT was worth. Now I understand why Medicare won't pay for it.
It's pretty clear that Medicare beats down the list prices on everything they pay for. Here's a somewhat humorous case I experienced. For a while after having the stents put in I needed to have my blood clotting ability checked each week so the anticoagulant dosage I was taking could be adjusted. I'd stop by my cardiac doctor's office and they'd check it and we'd decide how much we'd change the dosage for the following week. This usually took 15 minutes or so. I noticed on my Medicare statement that the cardiac doc's office was billing them $10 for each weekly test and accompanying chit-chat about dosage adjustment. Seemed like a bargain to me. Medicare was paying them $4.29.
Overall I'm very satisfied with Medicare and the healthcare infrastructure they've created for us. Your mileage may vary.