Of course you can make a better cure. Faster, less side effects, simpler route of administration, higher success rate,...
The patent is actually an argument for the cure. Because if you have a lifetime treatment, as the patent expires, anyone will be able to copy your treatment. It is called generic drugs and it is done all the time.
If you have a cure, during the time you have the patent, you will be able to treat everyone, both existing and new cases, and make tons of money while your competitors will have nothing. After the patent expires and your competitors will be able to copy your cure, only new cases will remain. Still valuable, but far less than when you had the patent and there were plenty of people to cure.
Goldman Sachs Analyst thinks otherwise. The company behind the Hepatitis C cure seems to also not doing well with monetizing their cure. There are also countries like Brazil that just suspended the patent.
The patent is actually an argument for the cure. Because if you have a lifetime treatment, as the patent expires, anyone will be able to copy your treatment. It is called generic drugs and it is done all the time. If you have a cure, during the time you have the patent, you will be able to treat everyone, both existing and new cases, and make tons of money while your competitors will have nothing. After the patent expires and your competitors will be able to copy your cure, only new cases will remain. Still valuable, but far less than when you had the patent and there were plenty of people to cure.