With insurers under such pressure, we’re now facing another sort of market dysfunction. Insurance companies are doing what they can to avoid paying claims. A recent report says that Obamacare plans average an 18 percent denial rate for in-network claims submitted by providers. Some reject more than a third. This suggests that even in a regulated marketplace like the Obamacare exchanges, insurers somehow manage to dispute nearly one out of every five claims.

These are systemic failures that can and should be fixed by regulation of the exchanges, better information on plan performance and robust competition. Unfortunately, consumers often still can’t make informed choices, and the options they have are limited.

But even if we fix these problems, there are two bigger factors looming that threaten the integrity of the entire system. Insurance at its root assumes that the payout required cannot be determined for each individual but can be estimated for the whole group. We can’t predict who will be affected by trauma or a broken bone, but in the aggregate, it is possible to estimate what will happen to the insured group as a whole. Some will suffer losses while the majority will be fine, and all will pay a fair average premium to cover the expenses that result.

Yet with the increases in chronic conditions and the promise of genetic information, these insurance requirements are not met. Someone with diabetes or rheumatoid arthritis will have the same condition and similar costs in each future year. And the woman with a positive BRCA gene is much more likely to develop breast cancer. In these cases, known costs simply must be paid. Instead of spreading these across all enrolled populations, they must be financed across time for the increasing numbers with such conditions. Loading private insurance companies with these expenses results in uncompetitive rates and market failure.

There is only one solution: pooling and financing some o r all of these at the broadest levels. In a nutshell, that is how we get a single-payer government system.

It is how we got Medicare. The cost of care to the elderly was known at the individual level for virtually everyone, so private insurance just wouldn’t work. So we had to finance this largely predictable cost through the government and its enormous pool of taxpayers.

It has been a tremendous, albeit expensive success. For the most part, people on Medicare like it a lot. This is the reason such a disruptive change is even a political possibility.