Stock holders demand that their CEO’s make the maximum profit possible. You cannot cover every citizen AND be the most profitable. Because stock holders must decide between either making the most money possible or covering every citizen with at least a basic package, this result is not surprising.
Medicare was enacted because seniors were deemed “ineligible” by free market insurance companies. If the free market could solve the problem, there would not be 50 million uninsured today, in addition to the countless under-insured. The public option would be there to cover those who cannot receive insurance through the "free market." With a public option, people will be paying into a government-run plan that insures them as opposed to not paying at all while the rest of us pay higher insurance premiums to offset the losses resulting from their care. As far as I can tell, there's no downside to correcting a clear market failure as we experience in this case.