Runaway health care costs

Health care system in the US is extremely expensive. Yet, it seems that quality does not necessarily reflect these costs. For example, it is sometimes argued that incentives are poorly set: doctors do unnecessary test of *insured) patients, who don't have many reasons to care about the costs.
Yet it seems at least possible if not plausible, that the US bears disproportionate share of research costs that lead to (significantly) higher prices of new treatments. I'm not sure how significant this can be, but maybe European systems are cheaper also because these system free-ride. Well, other reason can be that doctors cannot afford a Porsche in Europe (at least in Czech Republic).