You're right that there is far more to it than Alzheimers. Still, Quadmaster has half a point. It's probably not consumption (tuberculosis), or hookworm. It's much less likely than it was to be black lung. Even smoking is decreasing, though it will take another generation for that to show up in the old people.

So we're making progress. But we don't see it, because that becomes the new normal, and we see all these remaining things that cause problems for old people.

It could just be genetic luck, and the privelege that most people I interact with have access to the best treatment for diseases that have treatments, but around me the worst suffering is mostly alzheimers, striking in the late 70s to 80s.