Only a bit of the moon landing.
We have a bit lost the technology needed to send people to the moon and back. People that welded the Saturn V rockets are nowadays retired and the US manufacturing complex was slaughtered in the name of neo-liberist theories and fatter pay checks of C-level executives and finance firms.
Medicine isn't an exact science, so finding a general cure for an illness is difficult because everyone is different and every illness isn't the same.
100 years ago a type 1 diabetes was a sure death sentence, with the discover of insulin the situation changed dramatically.
I don't think that a simple pill will cure diabetes, but it's possible that the improvement will make the condition less and less problematic, if well followed.
If it's found what triggers the autoimmune response that onsets the T1 and if a screening, monitoring and education on what causes the onset of insulin resistance and then T2 diabetes is possible to prevent the illness.
Unfortunately from what happened to me and from what I read on this and other forums, the prevention side and the helping of the newly diagnosed is so low, we don't have a technological or scientific problem to resolve.
We have a social and health management problem, that it could be solved with the actual technology, but seem that nobody has the willingness to take that route.