But I genuinely understand your concerns.
I find this a bizarre way to assume that a person who has committed their entire lives to helping people would behave.
And people can become zealots for what they believe is best for others
Meanwhile private insurers definitely deny coverage to people with chronic illnesses (not everyone who is sick or dying is on Medicare/Medicaid). In a single-payer system those folks wouldn't slip through the cracks and .... the doctors would be incentivized to keep them alive! (assuming doctors are profit-motivated sociopaths like your average HN poster)
It's not complex, most of it is actually covered even in paramedic training. It's just that instead of sticking the ventilator tube in they inject some potassium chloride. Last month Costco was selling it for about 50 cents a pound. (Potassium salt for water softeners.)
The main cost will be the evaluation, not the procedure.
Consentment fraud is a lesser difficulty than stealing someone’s wallet at gunpoint or horribly mutilating people and leaving them in a bathtub. And yet, the consequences of this fraud are fatal, more fatal than extorting their entire life savings from a person. You just take someone who’s currently lonely, not really looked after, perhaps at odds with their parents… and hop, their life is over. Drug addicts, rape victims, lonely adults. So much taxes can be saved.
Easy fraud for doctors, with plenty of incentives to commit it, and the highest consequences for the victim.