If I understand him correctly DanielLC is saying that the cost-effectiveness of donating to VillageReach is greater than that which your post suggests because in the event of a Singularity scenario it could have the effect of allowing 28 people to lead very very long lives rather than just 1 person.
This is an important consideration. However there's the opposite effect that more people in Africa means more competition for already scare food and resources, and more people living anywhere also means all the CO2 that they, their livestock, etc. generate, whereas a frozen person consumes only the electricity for keeping their LN2 cool. If you think the Singularity will take long enough to make lives lost from global warming an important consideration, this is an influence in the direction of cryonics. Whether its enough to balance out the chance of 28 ve...
I've run in to the argument that cryonics beats VillageReach on a simple "shut up and multiply" level, by assuming an infinity vs finite tradeoff. Having read the Fun Theory sequences, it struck me that this wasn't a reasonable assumption, so I sat down, re-read a few relevant posts, shut up, and multiplied.
In Continuous Improvement, Eliezer ballparks a good fun-theory life as having a maximum length of around 28,000 years. In Robin Hanson's Cryonics Probability Breakdown, he assigns cryonics a conjoint probability of about 6%. 28,000 * 0.06 gives us a net return of 1,680 expected years.
Full body suspension from the Cryonics Institute currently costs $28,000.
VillageReach, according to GiveWell, can save an infant's life for less than $1,000.
For the price of Cryonics, we thus save 28 lives. 1680 expected years, divided by 28, puts the break-even point at an average lifespan of 60 years for those infants saved. A quick peak at Wikipedia suggests that the average African life is under 60 years for the majority of the continent, although there are some important nuances to really get a full picture.
Obviously, these are rough numbers, and I doubt many people base their decisions solely on "years lived". I do find it rather interesting that cryonics is currently about on par with one of the most effective charities in the world on that metric, however :)