> This might be a false notion, but I'm scared that the economics simply don't work to "cure" a major disease. It's more profitable financially to provide treatment to sick people.

Others have provided nice arguments as to why this isn't necessarily so, but allow me to add one more that is (I hope) more likely to appeal to a cynic.

This is one area where the corporate focus on short-term profits is actually working to the long-term benefit of humans. While it would be more profitable in the long run to sit on a cure and continue to sell therapeutics indefinitely, what CEO could resist the stock-boosting effect of a cure for a major disease? What a time to exercise your options! Long-term profitability is a problem for the next guy.