There's no single points of failure: as you get older, everything just starts wearing out and failing.
If you cure heart disease and cancer, then others will just take their place: strokes, respiratory disease, Alzheimer's disease, falls.
And even if you do extend your lifespan, the reality is quality of life at 90+ is a lot worse than in your 20s or 30s.
All my grandparents lived well into their 90s (mediterranean lifestyle + modern medicine), and all of them would’ve chosen euthanasia had it been an option (they phrased that in various ways - essentially something along the lines of “if God could bring me home now it’d be good”).
It’s been a sobering thing to experience and it leaves me hoping that if I’m ever in their position, that option will be available to me somehow.
Those really are the big two - as the graphs in the article show, the next biggest things are much smaller and much less likely to get you, which means you live a lot longer and healthier.
You don’t think we have been doing this already? Car safety improved, general violence, death by food poisoning, etc. Now we have contacts, knee replacement surgery, meniscus surgery, widespread information on fitness for the elderly, etc.
You have many specialized fields slowly improving. The top focus changes as the previous top problems get solutions.
This is why when somebody dies 'of old age' it's often not like you can just seem them slowly drifting away day by day. Rather they seem to be in perfectly good health, for their age at least, and then 2 weeks later, they're dead.