This is a bullshit "just-so story". In the wild most animals die long before they reach their age limit. There isn't enough selection pressure for evolution to spend resources to prolong life.
Evolution doesn't work on whole species. Or even individuals. It works on genes. If there is a gene that prolongs the life of an animal by 10 years, and it has 1.5x more babies in that time, then that gene will spread itself 1.5x more than the alternative genes. It doesn't matter if it's detrimental to the species in the long run. Lots of genes are.
Sure evolution needs death to work, but that's a very different claim than saying it selects for death.
Medical advances could definitely make you live to 200. We are very close to the ability to grow organs, and eventually entire bodies. Even if your body ages, you could just replace it. That would extend your life a ton on it's own. Add new brain tissue over time as the old stuff dies, and rejuvenate it a bunch with young blood (which has been shown to improve old brains a lot.)
Or you could get cryopreserved and wait until the really distant future, when have nanotechnology and gene editing and who knows what.
I apologize for the disillusionment that will follow:
1) Negligible senescence occurs mostly in organisms radically-different from humans and we have no idea how to edit those pathways into humans or if those pathways actually hold any value to humans. Hydra cells still die but the organism itself doesn't age. If you want to apply a gene-level anti-senescence therapy to an organism, you have to transfect the traits correctly into every cell of the organism--trillions of opportunities for catastrophic failure.
2) Gene editing probably has downstream cascades that we can't foresee.
3) Organ transplants become more risky with age, and the mortality risk from anesthesia does as well. If you were to replace your body, your brain would necessarily be the same age--and since we can't fix the (conjectured) senescence pathways in a living organism, you'd eventually be a senile individual in a young body. There's some neuroregenerative therapies that hold promise, but any "regenerative cell therapy" could also be read as "may create proliferative tumors"
4) Cryopreservation of a living organism is assumed to kill it, or at least alter it radically enough that its original functions will never be restored. Reconstructive nanotechnology is probably impossible due to heat dissipation and brownian motion--you'd have to hope that somehow a human scientist figures out how to engineer a new class of cell that is capable of navigating and repairing all extant human cells, which is more-or-less Clarke's Law.
We are not here forever. Oxygen metabolism literally rusts our bodies over time, disrupting and destroying countless pathways. Aging and death was part of the mitochondrial bargain. Tortoises have been evolving against the bargain's drawbacks for longer than humans have been around, and they still aren't immortal.
The point about negligible senescence was just to prove that aging isn't a biological necessity. There are animals that don't age, which means aging is neither evolutionary necessary nor undefeatable.
If we get to the point where we can edit genes, we could do it intelligently. Certainly better than random mutations and selection over tens of thousands of years.
Organ transplants are not trivial, but it's possible we could improve surgery and anesthesia, as opposed to curing aging directly.
a) I did mention that this wasn't a cure for aging, just a life extension. You've eliminated basically all the diseases that occur below the head and this would extend your life a ton.
b) It's been shown that younger blood rejuvenates brain tissue a lot: https://med.stanford.edu/news/all-news/2014/05/infusion-of-y... And cancer from regenerative therapies wouldn't be as much of an issue if you are in a younger body with a fully functioning immune system. It's also possible we will eventually be able to tweak the parameters of the immune system to help with that cause.
c) You can slowly add in younger brain tissue as older stuff dies. There was a study where they replaced all of the glial cells in living mice with human glial cells, just by injecting them with stem cells: http://www.medicaldaily.com/bringing-human-brain-mice-glial-... But you can also add new neurons over time too as the old ones die. This isn't as bad as it sounds. The new neurons would learn the patterns in the old neurons. Memories are highly distributed in the brain - you can cut out half of your brain and still function normally and remember everything. Most of your memories and personality would persist even as you replace your entire brain.
Cryopreservation is believed to preserve most of the information in the brain. The connectome is definitely preserved. Information contained within the cells is probably preserved at such cold temperatures, if it's even necessary. In the future it's very likely they will have the technology necessary to reconstruct a brain from this information. Reviving the brain tissue itself might even be possible because of how much is preserved, and how advanced technology might be.
> If you were to replace your body, your brain would necessarily be the same age
You could replace small parts of the brain with new parts piece by piece over time and maintain a continuous consciousness so a sense of self is kept. Whether it'd be really _you_ at the end of full replacement is up for debate.
Evolution doesn't work on whole species. Or even individuals. It works on genes. If there is a gene that prolongs the life of an animal by 10 years, and it has 1.5x more babies in that time, then that gene will spread itself 1.5x more than the alternative genes. It doesn't matter if it's detrimental to the species in the long run. Lots of genes are.
Sure evolution needs death to work, but that's a very different claim than saying it selects for death.
It's certainly possible to defeat aging. There are a number of animals that don't age at all: https://en.wikipedia.org/wiki/Negligible_senescence
Medical advances could definitely make you live to 200. We are very close to the ability to grow organs, and eventually entire bodies. Even if your body ages, you could just replace it. That would extend your life a ton on it's own. Add new brain tissue over time as the old stuff dies, and rejuvenate it a bunch with young blood (which has been shown to improve old brains a lot.)
Or you could get cryopreserved and wait until the really distant future, when have nanotechnology and gene editing and who knows what.