Earlier quoted context omitted.
By that logic, we should never have eradicated smallpox. Medicine extends lifespan - and a rising tide lifts all boats.
By that logic, we should never have eradicated smallpox. We eradicated smallpox for everyone , without distinction between rulers and ruled. That's the difference! a rising tide lifts all boats. "A witty saying proves nothing." -- Voltaire
Notwithstanding the daughter comment that disproves this, try substituting 'smallpox' for 'cancer'. Cancer treatment is by no means available to everyone, or even the majority, yet it extends lifespans (of good people and dictators alike). Should we not have developed treatments for cancer?