Suppose you've just had a newborn. The doctor offers to perform surgery on your child which 10% of the time kills them, and 90% of the time extends their life expectancy 30%. Do you agree?
I don't think so. All else equal, a 75 year old is more likely to drop dead tomorrow than a 25 year old (or healthy newborn) is, so the 10% death probability is less of a problem for them. Moreover, the years at the end of one's life are not quite the same as years of youth.
That's exactly why this is an _easier_ question for a newborn... the 30% is on their entire life and not their remaining years. Like, if the upside is living to 80 instead of 50, that's easier than it being the difference between living 5 months and 6 months.
