Most people with Medicare have supplemental health coverage that absorbs a big part of the cost.
Apparently you aren't on Medicare yet. It's become almost impossible to find doctors that will treat Medicare patients so they simply won't see elderly . After moving to Alabama we went over a year before finding one and that was only because my daughter's family doctor was kind enough to grandfather us in. Until then we were driving back to Tennessee to our family doctor ( 180 mile round trip)
With single payer, doctors have no choice.
Two things will happen.......there will be a severe shortage of doctors as they will not be able to survive on medicare ( or single payer) payments.
Those doctors who still are around will not be able to give elderly or terminal patients the care they require as they will not have time nor will they be paid adequately to stay in business.
Those people will get pain killers and best wishes.