Treatments Versus Cures

I have and had numerous relatives and friends who are members of the medical community including some in research. I broached the subject once of looking for "cures" for particular diseases. I was stunned to hear this physician say that "cures are not sought. If you cure a disease you are only paid once, but if you find a treatment, you have a patient for life". That mercenary aspect of medicine confounds me to this day.