[bipson]

Except that it is simply not true - the world is not that simple.

There are several incentives at play for a doctor.

Obviously there are different fields, and dental is slightly weird compared to the others, but first of all, doctors are trained to help and learn cures.

A doctor that keeps you sick instead of healthy is quickly out of a job (or out of patients, if you prefer). There are other doctors you know, and there is word-of-mouth, and ratings etc. There is no world-wide conspiracy of dental workers to keep you from getting a specific cure. Aka: Game Theory.

And an easy way to get rid of this would be if the doctors would be paid to keep you healthy:

So you pay as long as you are healthy, e.g. a valuable work-force. Hmmm, I wonder if you could just use income tax to fuel this...? Oh, we just invented universal health care, didn't we?

[bluGill]

Or even private insurance. There is a reason many insurance plans send you exercise right reminders all the time: healthy people cost less to ensure and so make more money.