The numbers are indeed optimistic, but they are based on empirical evidence:
my grandfather has already gained a decade partly as a result of my investment in a cancer research startup some years back
More conservatively, but still vastly optimistic, suppose $50k has a 1% chance of creating a remedy for a long-term remission (say, 10 extra QALY) in a lethal disease which strikes 1% of the population and that almost every sufferer can get the cure. This reduces the total expected years gained down to some 2 million, which is still nothing to sneeze at.
The numbers are indeed optimistic, but they are based on empirical evidence:
More conservatively, but still vastly optimistic, suppose $50k has a 1% chance of creating a remedy for a long-term remission (say, 10 extra QALY) in a lethal disease which strikes 1% of the population and that almost every sufferer can get the cure. This reduces the total expected years gained down to some 2 million, which is still nothing to sneeze at.