[kleiba]

there was a time, in the distant past, where you paid a doctor only as long as you were healthy

This sounds implausible, and even if it were true it would not be very fair: it's usually not the doctor's fault when you've got some medical issue, so why should s/he suffer from that financially?

[Tade0]

Also it creates a major incentive to disregard diseases.

What follows is that a dead patient, while not a source of income, is at the same time not a source of costs.

I don't see how such an arrangement could work long-term.

[_0ffh]

Right. I think I remember it used to be normal in some societies to pay the doctor only if he managed to cure you. That sounds much more plausible. Paying for the state transition from sick to okay should work just fine.

[bluGill]

The problem is if you can't be cured but can be helped. Diabetes is an example of something where with medical care you can live a long life, even though we can't cure you; but without help you are dead quickly.