Why is 16% of GDP too much to spend on health care?

That will be one of my questions tomorrow in the first class in Health Law. I remember, back during the debate over the Clintons' plan, the tongue-in-cheek report that, at the then-current rate of health-care inflation, in 50 years 100% of our GDP would be health care ("every man, woman, and child would be in hospital beds administering IVs to one another"). Now, quite sensible people (e.g.,