TL;DR: It's taking the standard premise that there's no such thing as dying from old age, and applying it to examining treatment for elderly patients. The curre

TL;DR: It's taking the standard premise that there's no such thing as dying from old age, and applying it to examining treatment for elderly patients. The current conception of a human lifespan is within the context of a world where medical interventions are preferentially given to the young instead of the old. Thus, a doctor might not recommend a course of treatment for a 100-year-old (who may be much younger, biologically) because of an incorrect belief about human lifespan, the 100-year-old dies soon as a result, and the cycle continues.