Sane healthcare would be one that addresses both sides of the equation... greed from unregulated for-profit healthcare that drives prices to insane levels due to supply and demand being broken (demand is infinite since people will give everything to live longer). It also needs to address the other side of the coin with highly-regulated universal health care, which is the lack of a free market to drive quality so things like wait times, availible medications, and other issues arise.
There are a few solutions to this but the best one I have heard is co-op based health care. Essentially healthcare where the owners are the patients of the companies they use, and there are no owners otherwise (so all owners are equal owners). When you move to a new healthcare company then you loose ownership in the old one and gain ownership in the new one.
This gives you supply-demand pressures that ensure your healthcare caters to what you want and need (or else loose their funding by patients moving), but keeps prices in check by eliminating the greed factor since any profits go back to the patients and insurance holders themselves.
Right now a doctor tends to be in the "network" of many insurances at the same time, not a single one. Presumably that would still be true under a co-op system. Obviously the size of a provider network would be one of the factors that would make one insurance more appealing than another, but overall id expect you to be just fine switching providers and keeping your doctor.
Also keep in mind with PPO type insurance you are never required to get a referral so can see any doctor at any time, with out of network being slightly more expensive.
That said no reason an insurance cant be open to any and all doctors at an appropriate price point.
As far as i know current insurance isnt prone to corruption as the major issue driving price, it is prone to greed, which is a legal though undesired factor that is very different from corruption.
As for the smaller co-ops not having negotiating power, since no insurance is driven by greed who would they competing against to negotiate. There would be no motivator for insurance to have **exclusive** deals. Doctors would want the largest networks, and insurance companies would want the largest, and there would be very little preventing that in most cases. Expensive doctors might prefer more expensive insurance, but if the patients of those doctors are likewise the owner inthe practice (not just in the insurance) even that goes away since the doctor is no longer setting their own price, their owner (the patients) are.
@freemo @argv_minus_one @stevebenen I'd think the bigger problem is that smaller co-ops wouldn't have negotiating power while bigger co-ops would need a management structure that would be very prone to corruption and operate not too dissimilarly from the current providers.
Then there would be the thorny questions of "can co-ops buy out or merge with other co-ops?" and "what happens when consolidation runs amok and anti-competitive practices proliferate?"