When you look at genetic/metabolic diseases, there are few examples of medicine actually reversing/curing the effects. This is because we have no methodology to efficiently and precisely change a person's genome to eliminate the disease. Even when we understand the disease fully, it is nearly impossible. For example, sickle cell disease is caused by a SINGLE nucleotide mutation... how exactly do scientist go about "fixing" it. You can't exactly open a person out, take a knife, and replace that nucleotide in every red blood cell and bone marrow cell in the body. Thus, medicine often works by simply substituting the missing factor from an artificial one. For diabetes mellitus, we give insulin to those who can't produce enough of it. But the entire suggestion that pharmaceutical companies are purposefully hiding a cure for many diseases is absurd. For one, this inference assumes humanity has a much greater amount of medical knowledge and technology than actually exists. Secondly, cures will be much more profitable than treatments. As long as the company sets the price slightly below the treatment, insurance companies will fall over backwards to pay for it (like they do with kidney transplants instead of dialysis); and even though the cure would be cheaper, the company would make magnitudes more, in profit, simply by having a monopoly on the cure for the first decade or two. And there has been HUGE advancements in the medical field... just look at cardiovascular disease and treatments for burn patients (we actually can grow human skin now). For diabetes, there has recently been new drugs working by indirect methods, such as increasing insulin production or making cells more sensitive to insulin. For many patients with type II diabetes, some of these drugs eliminate the need for insulin and only need to be taken every 24 hours... making the disease much more manageable than it was 10 years ago.