Under a single-payer system, would people be prevented somehow from spending their own money for services they want?
If not, then it’s not really single-payer. It’s just single-payer (Obamacare) for most people, while the rich and powerful access the best healthcare with their own money.
Socialized healthcare for thee but not for me.
Absolutely! There is also that a privileged caste of national politicians, bureaucrats, and Goldman Sachs personnel who will get essentially unlimited treatment at taxpayer expense. Rich people will always be able to go offshore where the best doctors and equipment will be, anyway. But even that won't be worth so much to either group when there are no more effective antibiotics. Public Health will not - cannot pay the cost of the R&D necessary to develop new antibiotics to replace/augment the current antibiotics that are continually losing effectiveness due to ongoing mutations in the pathogens. Then it is back to 1910 or so, medically speaking, you get sick, you die.