Terrible headline.

> the findings indicate that people in the most long-lived countries have experienced a deceleration in the rate of improvement of average life expectancy over the past three decades.

Lowering rates of improvement in life expectancy don't come anywhere close to indicating an upper limit to longevity is being reached.

For starters, improvement to life expectancy comes primarily from reductions in infant mortality. It's hardly surprising that in the developed world where infant mortality is already extremely low that we're not seeing the same rate of improvement that we did in the early 20th century. Most of the rest of improvements have likewise been reductions of pre-mature deaths, which have obviously benefited immensely from for example the introduction of antibiotics and better diagnostics.

People do live longer and are healthier in old age than they once were, but this improvement has always been smaller and slower. Basically if you reached adulthood in pre-industrial times you had good odds of making it into your mid 60s, comparable to your odds of today making it to your late 70s. There is no indication this rate of improvement has slowed down.

Further, the main complaint about the difficulty of making further improvement that the article complains about is specifically that unlike in the past where we were dealing with a small number of specific issues that kill people young, to make further progress we have to deal with actual aging, where there are a whole myriad of different problems that spring up as we get older. But that's the core issue - extending life does not mean dealing with age related heart disease or age related kidney failure or age related anything else; it means addressing the root cause of all these age related conditions so they don't start in the first place.

Life expectancy is also not purely based on physical medical effects. In recent years the US has seen dropping life expectancy, not because we have lost medical knowledge, but mostly due to deaths of despair. Suicides, drug overdoses, homicide, they all have an affect. While these are social ills that deserve attention, they mask real progress on the medical front.

Finally, besides rate of increase in life expectancy being a terrible metric because of life expectancy not corresponding to age at which people die, the specific rate of change is not simply a function of technical difficulty. This is primarily an economic question. It is plainly obvious that if every drug company decided to just stop pursuing a cure to some disease, progress would halt regardless of technical difficulty. In context, as time has gone on the costs (both in dollars and years) of developing any drugs have skyrocketed. That doesn't mean we're hitting walls across the board and this is the end of medical advancement, it means we're not flying by the seat of our pants anymore.

If we look at a better metric, the fraction of people living to advanced ages, that number has not only been rising, but the rate is accelerating. From 1950 to 2020 the percentage of American centenarians increased 10X, with the fastest increase in the decade from 2010 to 2020 [0]. Note that everyone in this graph was born before the discovery of penicillin. In terms of absolute numbers, the population of centenarians is expected to grow even faster in the near future [1]. And this all says nothing about the much more meaningful improvement to healthspan, allowing people to get more out of the years they have even if the number isn't much larger, which is the primary focus of anti-aging research at the moment.

[0] https://www.bumc.bu.edu/centenarian/statistics/ [1] https://www.pewresearch.org/short-reads/2024/01/09/us-centen...