It's true that no matter how you look at it, the USA spends a lot more per capita on healthcare relative to outcomes. But you have to be careful what outcome metric you look at. Like we're not doing great on life expectancy, but much of that is due to factors largely outside the healthcare system like violence, vehicle crashes, and lifestyle choices. And in other areas like 5-year cancer survival rates or new drug development we're at or near the top. Part of the problem in the USA is that we seem to be culturally incapable of admitting that rationing is needed, and that it simply isn't feasible to deliver excellent care to everyone, so political reform debates devolve into sound bites about "death panels".
The Affordable Care Act (Obamacare) set a minimum health plan medical loss ratio of 80%, or actually 85% for larger plans. And in practice most come in higher than that due to competitive pressures.
https://www.cms.gov/marketplace/private-health-insurance/med...
There's a huge amount of administrative overhead in dealing with health plans for things like claims and prior authorization. Much of that is imposed not so much by insurers themselves but by employers who want to hold down costs. Like a commercial insurer would be happy to sell a plan that would pay every claim immediately at 100% with no questions asked. It would be less work for them. But no one would buy it because costs would explode. Medicare and Medicaid plans also have prior authorization and peer review processes. Something like a quarter of all healthcare services are "low value care" which doesn't align with evidence-based clinical practice guidelines and may even harm the patient, so when health plans apply review processes the right way then ideally it's better for patients and holds down costs for everyone.
To be clear, I'm not here to defend commercial health insurance companies. They are part of the problem and some reforms in that area are sorely needed. But let's have an honest debate about it and stop pretending that eliminating them would solve the deeper systemic problems.
Also not saying you're wrong about many healthcare services being unnecessary or even harmful, and someone has to be the one to say no to patients asking for low value care which is definitely a real hard position to be in and a real problem. At the same time insurance companies aren't making a great case for themselves as the solution imo bring on the government death panels.
In general though I'm just skeptical that a single payer solution is the best possible long-term approach. US federal and state governments are already under tremendous fiscal pressure. So if we forcibly route all healthcare payments through governments then there's going to be constant pressure to hold down costs through blunt measures. And decisions will inevitably become even more politicized with special favors or punishments given out based on party loyalty. Do we really want to put someone like Xavier Becerra or Robert F. Kennedy Jr. in charge of centrally planning something like a fifth of the US economy?
The current US healthcare system is unnecessarily wasteful and cruel. But on the positive side we produce far more innovation per capita than any other country. Let's find a way to incrementally fix the worst problems without killing the golden goose.