I'd say a healthy person has a lot of added value compared to a sick one.
EDIT: Clearly a controversial sentiment, I know.
I think you were modded down for insinuating that the issue is simply one of whether "healthy people are better to have around than sick people", and thus that knb is trivializing the value of healthy people. This is a ridiculous position to impute to someone, and doesn't help the discussion.
knb's point (on any charitable, contextual reading), is that doctor's aren't responsible for most of the health that exists ("Doctors add little net value"), not that "making people healthy adds little value". Comments like yours -- tarr...
A feature in Scientific American magazine casts some light on the troubled state of modern medicine.
Health Care Myth Busters: Is There a High Degree of Scientific Certainty in Modern Medicine?
Short excerpt:
Scientific American often gates its online articles after some time has passed, so I don't know how long it will be available.