XKCD 871: The problem of scaling the sane use of money is a problem of not crushing people's wills, not a problem of money being a limited resource. It simply isn't true that money spent on cryonics comes out of Givewell's or SIAI's pockets, unless you're Rain, which is why I'll accept that answer from Rain but not from you.
From Mike Darwn's Chronopause, an essay titled "Would You Like Another Plate of This?", discussing people's attitudes to life:
Conclusion, graphs, and references in article. As usual, I recommend reading Chronopause.com as Darwin has many good articles; to quickly link a few: