If we knew that we probably wouldn’t need AI to tell us.
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.
I don’t think that lack of intelligence is the bottleneck. It might be in some places, but categorically, across the board, our bottlenecks are much more pragmatic and mundane.
Consider another devastating disease: tuberculosis. It’s largely eradicated in the 1st world but is still a major cause of death basically everywhere else. We know how to treat it, lack of knowledge isn’t the bottleneck. I’d say effectively we do not have a cure for TB because we have not made that cure accessible to enough humans.