Because we're not good at curing cancers, we're just good at making people survive better for longer until the cancer gets them. 5 year survival is a lousy metric but it's the best we can manage and measure.
I'm perfectly happy investing roughly 98% of my savings into the thing that has a solid shot at curing cancers, autoimmune and neurodegenerative diseases. I don't understand why all billionaires aren't doing this.
But realistically: perhaps by noticing patterns we’ve failed to notice and by generating likely molecules or pathways to treatment that we hadn’t explored.
We don’t really know what causes most diseases anyway. Why does the Shingles vaccine seem to defend against dementia? Why does picking your nose a lot seem to increase risk of Alzheimer’s?
That’s the point of building something smarter than us: it can get to places we can’t get on our own, at least much faster than we could without it.
But people accept the status quo and are afraid to take a moment’s look into the face of their own impending injury, senescence and death: that’s how our brains are wired to survive and it used to make sense evolutionarily until about 5 minutes ago.
...Meanwhile, we are developing techniques to yes, cure some kinds of cancer, as in every time they check back it's completely gone, without harming healthy tissue.
We are developing "anti-vaccines" for autoimmune diseases, that can teach our bodies to stop attacking themselves.
We are learning where some of the origins of the neurodegenerative diseases are, in ways that makes treating them much more feasible.
So you're 100% wrong about the things we can't do, and your confidence in what "AI" can do is ludicrously unfounded.
I’m not claiming we haven’t made a dent. I’m claiming I’m in roughly as much danger from these things right now as any human ever has been: middling results.
If we can speed up the cures by even 1%, that’s cumulatively billions of hours of human life saved by the time we’re done.
And that hypothetical "billions of hours of human life saved" has to be measured against the actual damage being done right now.
Real damage to economy, environment, politics, social cohesion, and people's lives now
vs
Maybe, someday, we improve the speed of finding cures for diseases? In an unknown way, at an unknown time, for an unknown cost, and by an unknown amount.
Who knows, maybe they'll give everyone a pony while they're at it! It seems just as likely as what you're proposing.