There are many problems with this question. You make the mistake of generalization by assuming that "the elites" are one monolithic group with a unified goal. Your premise that this goal is immediate extinction of the masses is flawed beyond repair. You have a false dichotomy: course of action A versus course of action B. You reveal your hidden premise in a follow-up sentence, which is that the vaccines contain poison. Your unrevealed hidden premise is that the poisoned shots are the chosen method of exterminating mankind.

That said, how many people dying from the drinking water do you think it would take before people figured it out and took steps to mitigate it? How long before people determined what was making it happen?