Health insurance company margins are 3% to 5%. The book America’s Bitter Pill: Money, Politics, Back-Room Deals, and the Fight to Fix Our Broken Healthcare System (2015) by journalist Steven Brill blames mostly wasteful practices in hospitals, pharma and device manufacturers, government and corporate health administration costs.
Not to dismiss your point, but the US healthcare system has one meta problem.
Complexity.
There are too many parties. There are too many bespoke party-party contract. There are too many new middle-parties being created, with their own contracts. There are too many systems. There's too much tech debt.
That's a reason improvements to the US healthcare system have generally been via HHS/CMS imposing standardization mandates ('or no Medicare payments').
But providers, facilities, and insurers (most operating on low margins) can't be collectively more meta-efficient without simplifying the system.
Single payer / Medicare for all is a critical start not because of coverage, but because of simplicity.
There are so many intractable problems with the current system simply by virtue that changing anything about them requires 100s of parties to update 10,000s of party-party contracts and interfaces.
That's the biggest source of waste in the current system: constant duplicative re-engineering.
Thanks for the recommendation.
US health insurance margins are thinner than European private insurance. Their administrative cost however are 9-10%, when in Europe (or really, France and Germany, I haven't looked elsewhere) they are 5-8%. The difference is probably in negotiating costs and audits. But that means that in total, for every 100 dollar paid, US insuree pay 4-10 dollar in efficiency+dividend that a European doesn't.