Hmm. I'm not so sure. Some doctor was telling me about a brain surgeon he knew, who'd gone through medical school (5 years), spent time as a junior doctor (2 years), taken a Phd (3 years), gone on to train for this that and the other, and finally arrived at the top of his game, fully-qualified...
...but with only 10 years of working life left, in which the NHS could exploit his undoubted high level of skill. And apparently he wasn't untypical.
How does that make any sense?
I'll admit that there may be jobs were retirement comes too early. But consider that when he is finished he is fully qualified and educated with the most recent methods and insight. 10 years later, science has moved on and those methods are not the best available any more. So someone new might be better than him, just because his education is more recent. 100 years later all education from a long time ago is essentially useless. Would you want your brain to be operated on according to procedures established 100 years ago? That was even before lobotomies were a thing.
It obviously depends on how fast a field is moving. If things are still done like they were 50 years ago, someone who has been doing these things for 50 years has extremely valuable experience. But especially science is very fast moving on human timescales.
It used to be the case that one man could acquire all the useful knowledge available in his lifetime, and be a proper Renaissance Man. This hasn't been the case since, I don't know when, 1700? I doubt it could ever be the case again but it might be more possible with a longer life time.
With some simple reasoning one can tell that longevity does not help here: Let us assume it takes me 1 year to find out something new and write a paper on it. Let us also assume that it takes me 1 day to fully understand such a paper. If I want to stay productive, I cannot devote to much time on reading papers of others, say less than 1/10. That means all topics I stay fully current on cannot exceed the output of 36 scientists. As long as these 36 scientists keep working (or have a successor) I cannot expand the number of topics I am fully current on, no matter how long I live. I can expand the number of topics by dropping the fully current requirement for some of them to have more topics I have a basic understanding of. But to be able to expand the knowledge about a certain topic, I need to be current on it.
If with advancing age, it takes more time for me to understand a new finding, because I need to overcome my preconceptions that I have acquired, I have to reduce the number of topics I am current on, or have my students worry about the details and just tell me the important things (which means that they are essential in expanding knowledge.)
In short: Specialization is always necessary in science and longevity is not a way around that.
And if you can increase longevity, mightn't it be possible to increase the plasticity of the ageing brain at the same time, anyway?
In brief, you may be right, but I see no obvious reason to agree with you.
I was assuming that this is the case. Otherwise longevity would be even worse.
Edit:
But what are we racing? Why does it need to be faster?
I am not saying we need to be faster. I am just saying we will be slower with longevity.