The bar to entry in the pharma market is extremely high. You need a lot of capital to enter it, which quickly disqualifies 95% of the population.

Now of course, people without money can still get funding from investors. But those investors are already racking big profits from the continuous model of insulin treatments. A cure would be a detriment to their profits, so it's not something they're interested in funding. Not all pharma is insulin, but it's one of the bigger pharma industries.

This isn't to mention that if you were one of the 5% and managed to have the resources to find and produce a cure, that the other mega corporations (with more funds than most of those 5% individuals) wouldn't engage in anti competitive practices to shut you down. Many companies had good products but still ultimately failed.

Unfortunately capitalism does not allow innovation to flourish like many of us were taught to believe.