I agree that those have bigger bangs, but the "buck" part for vaccines is extremely small. Good plumbing and sewers have probably saved a lot more lives, but the cost per person is orders of magnitude higher.

For example, the cost of eradicating smallpox was about $1-2 billion (in 2017 dollars), and saves around 2 million lives per year. (This is a rare example of a one-time investment that pays off forever with no additional action on our part, which is pretty nice.) This is about what New York City spends annually to maintain city water and sewer infrastructure.

For one, those are still way more expensive than vaccines. With $100 for vaccines (whose research costs have long been absorbed anyway) you're settled for life, but you'd be paying for trash collection, indoor plumbing and refrigerators/freezers for your whole life.

(Plus those are not medicine, which is the context we were discussing here).