Cancer is not a simple, one-size-fits-all disease. There are many different types of cancer. For some of them there is a cure. For most there isn't. Yet. We don't even fully understand all forms of cancer yet--how and why they start, why they continue, how they are able to bypass normal body controls, why sometimes they simply stop. We know far more about cancer than we did 5, 10, 20, 50 years ago, but biology is not simple like Newtonian physics--you can't just plug numbers into a "cancer equation," press the ENTER key and crank out an answer. It takes, literally, millions of man-hours of hard work to try to figure out what's going on, and when you think you've got nature figured out "she" throws you a curve ball. With regard to HIV, we still don't even have a full understanding of the normal immune system--it turns out to be far more complex than was once thought--let alone how the immune system interacts with the HIV virus.
Right now, science and scientific research is far more incomprehensible and far less important to the average person (and therefore their representatives) than Jersey Shore or the Final Four, or prayer in schools. How many "average joe's" out there even know the difference between valine and valium? We have school boards in some states promoting the teaching of nonscientific religious nonsense in science classes. As long as it stays that way, as long as kids can make more money trading derivatives or doing marketing than doing science, then progress is going to continue to be slow. As long as big pharma's R&D budgets are heavily weighted toward MARKET RESEARCH, as long as they can make more money selling Cialis to horny old rich guys sitting in bathtubs who otherwise can't get it up than it can selling antiretroviral drugs in Africa, then the present situation will continue.