A truly free market would not be unsustainable for anything but catastrophic insurance. It would certainly create some elite insurance plans. Some would have worse insurance or none at all. It all depends on how much of a catastrophe you think having no/poor health insurance is.
Unless one has the ideological blinders one in favor of government solutions to everything. . . . the reality is dawning on almost everyone that the real catastrophe is the Affordable Care Act.
Employers have, en masse, resorted to evasion of the expenses it imposes on them in a probably vain attempt to remain solvent. They have cut back on the number of employees, and cut the hours of as many employees as they dare to keep them under 30 hours, and the total numbers of employees under the thresholds where mandates apply. They have also cut wages because they can't afford the costs of their labor.
People have chosen, in large numbers, to simply drop out of jobs in order to qualify for government-subsidized "care". Our entire economy is going into a tailspin and we are heading for the levels of prosperity only marxists have achieved, historically. . . .. mass shortages of goods, services, and everything else people can ordinarily produce. . . . even rationed health care that will mean a lot of folks simply won't get any care at all. . . .
To be certain, a lot of production is moving out of our country even while our cartelists are importing virtual slave labor under "Amnesty", as well.
Housing prices, and prices in goods and services in every segment of our economy will also be dropping like lead balloons while people earn less, and pay much much more for the little health care they can afford. . . .
Stock prices will ultimately plummet as well because even the trillions of "economic stimulus" funds being handed out by the Fed and even directly invested by the Fed in various markets, are an unsustainable sort of influence. In the end, it is only actual earnings that can "prop up" investments from whatever source, and there is no way our 'sugared up" markets are not just another "pump and dump" operation courtesy of our economic planners, who are delusional at best.