Much more needs to be done to push employers out of the health insurance market. Most of the reforms now being touted, by Democrats and Republicans alike, aim to do the opposite.
...You could give everybody a voucher (which could be used as partial payment for a more expensive policy) and recover the cost from general taxation. Or you could give full vouchers only to people on low incomes, tapering the value to zero as incomes rose, again asking taxpayers to pick up the check -- and in this case also mandating that everybody buy at least the basic plan. You could satisfy the "ignore pre-existing conditions" criterion either through regulation or by adjusting the value of vouchers according to health risk. The cost would depend on such details, and many more besides -- but you can be sure it would not be small.
I can understand why no Republican contender for the presidency is proposing this. Only a very unusual Republican would suggest a significant rise in taxes to mainly benefit the least-well-off. But why is no Democrat proposing such a scheme? Because it is politically more appealing to pretend that this great and long-overdue social advance can be achieved mainly at the expense of greedy employers (and grasping insurance and pharmaceutical companies).
The original sin of America's health care system is employer-provided health insurance. But:
--the workers who have it are generally happy
--labor unions don't want to lose it as something they can bargain for on behalf of their members
--many, many people are under the illusion that the cost is borne by employers, not by workers
So from a political perspective, no one wants to take it on. Instead, they try to graft health care reform onto the employer-based system. Which is like trying dance therapy on someone suffering from congestive heart failure.