Megan McArdle looks at historic levels of health care spending across the world and makes a good case that Americans pay more for health care because of the tax subsidy.
Recall that John McCain proposed eliminating the tax subsidy for health care but the idea was shamelessly demagogued by the Obama campaign. (For example, they dishonestly portrayed the proposal as a tax hike, ignoring the tax credit that would compensate for taxing health benefits.)
Also note that the health care nationalization act does nothing about the problem, other than an excise tax on high-value plans that probably will never take effect.