Some chronic diseases are, quite frankly, money makers. I know this because I work in the Healthcare industry on the Medical Diagnostics side. We have products that are used to help diagnose & treat chronic health care problems. These are big money makers for the company, and ultimately pay me. If these chronic illnesses are no longer an issue, I'm sure the workforce around here would decrease.

But on the other hand, if those chronic issues were cured, other diseases, illnesses, injuries would take place. I don't believe that we live in a world where all sickness and disease will ever be cured. And just thinking of it this way, even in our imaginations of the future (Star Trek, Battlestar, Firefly, etc) there are illnesses and disease (not just injury). It is something we cannot imagine.

Just think of it this way...a greedy corporation may want to supress a cure, but all it takes is one scientist personally effected by a disease, and you have an advocate for a cure. Money can also be had in making a cure (or preventitive)...look at vaccinations.