Life expectancy rise in rich countries slows down: took 30 years to prove

As I said down thread, this could just be a potato/potahto thing? If this is just definitionally beating getting frail, then that makes sense. But I don't know that I could pin down an age that I would want to freeze progress at. Nor do I think I expected that there would be a general age to freeze aging at. Let me keep my strength longer, but I expect I will be/look/appear older and older the older I get.

Now, granted, I'd be delighted if I have the same strength my 90 year old grandfather in law did. In his 70s, I'm pretty sure the only thing I could beat him at was a race. Lifting things or doing manual work outside, and he was far beyond what I was in my 30s.

I have a suspicion that something is being miscommunicated between you and many others here. (I admit that I might be wrong. But hear me out.)

It sounds like you are thinking about the visual signs of aging. Like wrinkling of the face, or salt-and-pepper hair. That kind of thing. And sure, there is a lot of vain people who would like to stop that from happening.

But in general the aging people want to defeat is not the wrinkled face. It is things like our immune system demonstrably going to crap as we turn older. Or losing muscle mass. Or becoming senile. Or our bones becoming more fragile.

For young people the flue is basically an inconvenience (by and large). But as we age things like seasonal flue becomes huge issues. People's immune system used to work for decades without a hitch, and then suddenly it decides to crap out. Why?

I can also put it into a more mathematical framework. If maybe that helps? Imagine plotting the probability of a human dying in their x'th year assuming that they have survived before x-1 years. If you plot this now you would see a sort of bath-tub like curve. There is some chance a newborn dies in their first few years of life due to birth defects. Because of that the first few years have a higher probability of death. Then the plot plateaus, and the probability remains basically constant low number for multiple decades. People can still die due to violence, or accidents, or random health issues, but the chance of that doesn't really change much from year to year. And as you approach the other "side" of the bath-tub you see that the probability starts climbing again. And this climb is quite rapid. By the time you are 100ish (plus minus a few years) you have fairly good chances of dying in any given year. And then around 105ish you have about even chances of dying or staying alive in each year. And then we don't have anyone who ever lived to 130.

On this kind of plot if we were to defeat aging what you would see is that the plateau remains constant. That is the chances of a 35 year old dying in the next year where the same as the 135 year old dying in the next year.

Which is why I balk at the framing of "defeating aging." We want to defeat the decline that comes with advanced age. But this doesn't necessarily mean we have to freeze the clock at some age, as it were. May be that that is the way it happens.