I fully agree with this point, and I fully agree with Page's goals. But I think there are things here that a simple total-years-of-potential-life-lost framework can not capture. As you might have guessed even from my first comment, this issue is very personal to me. Not long ago a good friend died after terrible suffering, leaving three young children behind. That's very sad, and I really don't know for what values of N could this be balanced in a utilitarian sense by lengthening the healthy old age of N of my friends with 10 years. Obviously, such trade-offs are taboo, but even if I try to force myself into some detached outside view, I still believe that number N must be large.
Agreed that not all years are equal, and the impacts of early deaths can be large.
For measuring N, I wonder how much of this is availability bias. I know a number of old people who have outlived half of their friends, as well as seeing a few friends lost early in life. My weak suspicion is that they would favor a lower N, just by more familiarity with death due to old age and a better idea of what old age deaths do to the culture / friend groups / family.
Google's announcement, Time magazine rather sensationalist headline.
In any case, it's nice to know that Google set its sights to "challenge ... aging and associated diseases". Apple's Tim Cook:
For too many of our friends and family, life has been cut short or the quality of their life is too often lacking. Art is one of the crazy ones who thinks it doesn’t have to be this way.
One more step towards "world optimization".