>Medicine has failed us (mostly).
It never promised to be perfect. Medical research is shit, I'll give you that, but it hasn't failed.
>Millions of people are dying from heart failure, cancer, kidney failure, etc.
Because they're getting old enough to die of that instead of a rock to the face.
>What if we tracked everyone who healed their diseases and tried to make associations between lifestyles, diets, whatever, and their cures?
Having access to a lot of good data would be useful, but short of a dictatorship whose sole purpose is to make a huge and inefficient experiment you won't get good data on millions of people.