What should the objective be? Higher staffing? Higher pay for professionals? Higher standard of patient care, at lower cost?

There is no right answer. All of those people are stakeholders in the health care system. We tend to be solicitous of the interests of workers, even when squeezing those workers would have benefits for taxpayers (which is why we have unions for public sector jobs).

But regardless of the "should" questions, there remains the "is" question. Health care costs are higher in this country because we pay people more to provide health care services to people than most other countries do. There is no way to change that without paying people less to provide health care services than we do today.

So if your plan for transitioning to single-payer depends on deep cuts to the amount of money we pay for health care spending, you have to account for the fact that there are tons and tons of people on the other side of that. Ordinary people, hard-working people, people like doctors and nurses and orderlies and whomever that are sympathetic in any political context. Roughly 12% of the workforce is in the healthcare sector, so slashing that sector by 60% is going to affect a lot of people. You'd have to do what virtually other single-payer country does - set a price list for services and squeeeeeeeeeeeze the providers as much as possible.

"Should" we do that? Don't know. Doesn't matter, in this context. This is an "is" question. We do pay a ton more for health care than other countries. So if we want the single-payer system that other countries have, we either have to: i) stop doing that; or ii) pay a shirt-ton more for health care than we do now. Both are political poison. Which is why we don't ever switch to single-payer systems, even in states that really really really want to.