Extra tangential: For a lot of human history, many of the elite _thought_ they were close to achieving immortality through unlocking the elixir of life, and that it could be discovered in the next few years.
That elixir has changed names, but the concept is still around.
Except that this time the elixir isn't powered by magic or fairy tales.
Aging is just another biological process. It's controlled by genetics and environment like everything else, and can be manipulated using similar principles.
It seems likely (thinking of CRISPR and similar inventions) the rudimentary tools for controlling aging are coming of age. I believe biological immortality is closer than we think.
Sorry to burst your bubble, but aging is not "just another biological process". It isn't even biological... everything ages and decays, even inorganic matter. Even rocks decay into clay.
Living biological processes by their nature resist decay, but that's an uphill battle... eventually entropy wins. Errors and waste products accumulate, materials become brittle and fragile, with every year lived the probability of dying before the next increases.
Can we help our biology to become more efficient at maintenance and repair? Probably, but not all that much. We are already very long lived. The only complex terrestrial beings that live longer do so by living very slowly... in terms of subjective time experienced, maybe they don't live any longer at all.
I posit that you've just found the name or class of elixir of our times. I'm not denying that life expectancy can be increased due to advances in science, healthcare, medicine, and lifestyle changes. But there's a difference between extending by a few years or even decades every century or so and immortality. We will discover other aspects that become limiting factors. Aging as "just another biological process" is a drastic oversimplification in my opinion and I think the more accurate statement is our understanding of aging has grown, but I doubt it's complete.
Something I've thought a lot about: in most fields of study, modern scholars revere the 'old masters' that came centuries before for their genius: think Newton, DaVinci, Socrates, Galileo.
However, in medicine, most doctors will tell you that the doctors from 200+ years ago were idiots that did more harm than good.
Why is that? Is modern medicine too hubristic? Were the doctors of ages old really that dumb? Is this a trend that will repeat itself in 200 years?
The first doctor discovered washing hands improved outcomes ~174 years ago & was initially dismissed[1]. It was later confirmed a couple of decades later when germ theory & bactereology[2] was born. Our understanding of how to have successful organ transplants only really took off in the past ~80 years as doctors started to better understand rejection. At the same time, in the 20th century, we got all sorts of new scanners & equipment to visualize the internals of the human body that we've never had before. Finally, the 20th & 21st centuries brought along revolutions in computing, genomics, & pharmacology.
So yes, 200 years ago doctors knew a great deal far less than today. I'm sure a doctor 200 years in the future looking back on today will feel similarly. There's still so much we don't know & there's a lot of guesswork involved. I wouldn't say they were idiots but the outcomes were certainly not at levels we'd accept today (just as the outcomes today won't be acceptable 200 years from now).
FWIW, the same is true in other disciplines. The 20th century marked a rapid exponential curve in learning. No one really studies any of the masters you note except for maybe Newton & Galileo. The former because the kinematics equations are actually extremely good approximations for Einstein's equations (& also his work on light and lenses remains accurate and foundational to this day). The latter as a warning of the dangers of putting ideology ahead of science and scientific thinking. Galileo's heliocentric model isn't actually used today except as a way to teach kids about the solar system because it's really simple & is good enough at that level (his work on gravity was an important influence for Newton's ideas on the topic).
High school science still (afaik) teaches the Bohr model [1] of the atom, because it works well enough for that level. This also leads to a great moment the next year when the teacher leads off with something along the lines of "Remember the Bohr model? Well, forget it: it's wrong." Fun that this causes some students to be outraged, but it's also a great lesson in the scientific method - or at least my (excellent) science teacher used it for that and it made a lasting impact on me.
I'm still annoyed whenever I think back at that, at being taught something that was wrong as if it was true. It costs nothing to say, "We're going to learn a model of the atom - the reality is more complex but this will work for now."
The way it is often done just creates trust issues for people who really care about accuracy...
That elixir has changed names, but the concept is still around.