Perhaps I should clarify. When people talk about giving altruistically, most of the ideas discussed involved some form of charity donation (like the example you gave of a $2 cholera vaccine). As someone who works within the health care field as a biostatistician, I am well aware of how vaccines can save lives, and I fully acknowledge that saving lives have "real world impact".
My point (such as it is), is my belief in how such vaccines (or any other discovery) is made. My interest is in basic science, which is the bedrock of all other scientific and technological developments, including those that could directly benefit all of humanity. The primary source of funding for basic science comes primarily from governments -- and many governments across the world have been under pressure to reduce such funding as part of overall fiscal pressures on to keep control of their budget, or have cut them to fulfill a political agenda (most recent example, the tax bill that has passed the US Senate).
To me, if I had somehow won a large amount of money, say, through a lottery, I would want to create or fund an alternative source for basic scientific research that is accessible to all scientists. But $10 million is simply not enough to do so (as
@Vanadium 50 has already indicated here on this thread). An order of magnitude of $10 billion might be more meaningful.