That's an interesting point. I am signed up for cryonics, but I'm actually rather ambivalent about my life. One major wrinkle is that, if cryonics does succeed, it would almost certainly have to be in a scenario where aging was solved by necessary precursor technologies. For me, a large chunk of my ambivalence is simply the anticipated decline in health as I age. By the same token, existential risks that might prevent me from, for instance, living from age 75 to age 85 tend not to worry me much.
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: