It may be that some will refuse the medicine, or that others will stop taking the medicine before being fully cured. It happens in life that way. There is no expiration date on the medicine the Buddha leaves for us. The medicine the Buddha leaves us in the Lotus Sutra is always good and is always available, even if it appears the physician has died and left us. The medicine, and through the medicine the Buddha, is always available for us to take and benefit from.