>>When it is YOUR life on the line, you may very well be willing to pay significantly more for those diminishing returns; they may be diminishing, but they are in fact greater returns.

There is no evidence that this is the case. Note that the vast majority of the cost is due to the massive complexity of the system: every party involved - and there are many - wants their cut, and they don't necessarily contribute to the well-being of the patient or the efficiency of the process.