One comment regarding the yearly progress of the cohort rate. I would think this would fluctuate with significant medical advances (e.g. the first few years that bypass surgery/artificial hearts started to be used). I can't see how medical progression is perfectly linear at 1.0%/year.
In the UK (population 70 million), 28,000 heart bypass operations happen per year. The number of people who will have one is in the low single digits as a percentage of the population.
Even for those people who do have one there is no guarantee that it will have a significant impact on their lives. Yes for some it will but for others it's only reduced one possible cause of death and a lot of the behaviours that lead to heart problems also lead to, say cancer, or diabetes, or liver failure, or something else that will cut your life short.
Then compare that to the thousands of small improvements.
I can see it might not be constant over an extended period, but I don't think there are many, if any, things that would cause a significant spike.
While it's hard to predict, I personally wouldn't bet against a game changing spike in the coming decades. It's only very recently that medicine has started riding Moore's law. Robotics and miniaturization are speeding up basic research by orders of magnitude.
I don't think it's unreasonable to say that biology has achieved more in the past two decades than in all preceding history. And there's no sign that the exponential is running out.
Granted, there may be fundamental limits that we don't appreciate yet. That's the whole draw of science, we simply don't know.
You may be right but there will still be bottlenecks in the process around patient trials and the more "manual" stages of any treatment.
I think the next big improvement will likely not register on life expectancy because it will be in response to a specific problem. The next generation of anti-biotics for instance will have a massive impact but will likely only cancel out the negative impact of drug-resistant strains of bacteria.
This makes sense - medical advances won't be widely adopted immediately, then there will be a gradual acceleration of adoption (and improvement rate) once its benefits are proven and costs come down, and then no further contribution to improvements once wide adoption is the norm.
What you also tend to see is that advances affect improvements by year of birth more prominently than by year of discovery. In the UK we have a 'golden cohort' for example, which you could Google for more info.
Spikes do tend to occur during and after big causes of death (spanish flu, world wars) as the improvement rate drops sharply and then recovers again.