One continuing problem with ALL means of sharing risk re health costs, via insurance or government action, is the reality of rationing. Government systems of health care are frequently tagged with the stigma of "rationing" care, which they DO do. There is only so much medical care available, so any systemic approach should recognize that prioritizing the $$ and medical man-hours available will happen. One solution to the stigma is openness, which too many government programs avoid.
Example: The current VA treatment system promises care for ALL eligible veterans. In reality, the total care allowed ( by the $$ allocated to the system ) is way short of demand, particularly in psychological help. The VA effectively "Rations" health care by having several un-acknowledged barriers. Their facilities are sited physically in places remote from the largest populations of veterans in need. Their admittance criteria are time consuming & records intensive, with minimal assistance for the needy vet. While the VA itself publicly claims to want to treat vets, the vets who need treatment see a huge maze, which effectively blocks & delays their access to the treatment they need. THIS is the system I expect to find when there is only one source for all health care.
While the current Insurance system does have costs, which I would like to think can be reduced, it does have ONE singular advantage: the public has the government on IT's side in disputes with the insurance industry. With a single-payer ( Government ) system, it is ME, alone, against the entire government when I need access to the system. There will be no independent forum to argue my needs in. If you think I am wrong. the OTHER example of government managed care is Medicare. Try getting a change to their rules for care-givers!!
ANY new system of cost allocation needs to start by understanding and discussing the rationing which WILL occur. The new system must have some explicit PUBLIC forum for continuous review of both individual cases, and systemic reforms. This system MUST be quick to review & decide: Medical care delivered late is NOT caring! British medicine has long depended on delaying expensive treatments to decrease their total costs: their incidence of Heart bypass operations & Kidney transplants is tiny compared to ours, and most of their candidates die waiting!
I spent my childhood & 7 years after college in the active military medical care system. I am now stuck in Medicare for the rest of my life. Both systems can do a good job, with the right assets. Both can be totally non-functional in individual cases. I worked for 30 years in the employer paid insurance system, which has it's own negatives: Lock-in or non-insure-ablity being one major issue.
None of those systems is what I want for my grandchildren ( when they arrive).