That’s oft-repeated but makes no sense. If you develop and patent a treatment, then that necessarily means that the cure—if it exists—is out there and unpatanted, for some other company to develop and sell. There is an economic incentive for them to do so, because a cure is obviously more valuable than a treatment. It would be very weird if you could somehow make a treatment more valuable than a cure by changing how you charge for it. By that logic, companies would never sell cars, only lease them.