The Buddha said, there are three types of sick people: there is the one who will recover from their illness only if they receive medicine, nursing, proper food, and other care - and will not recover if they do not receive these things. There is also the one who will not recover from their illness, even if they were to receive all the proper care. And there is the one who will recover whether or not they receive care.
Though it is unknown whether a sick person will benefit from care, care is nevertheless given to the sick. Though it is just as reasonable to fear that a sick person will not benefit from care as it is to hope that a sick person will benefit from care, it is not the hope that guides the provision of care: there are many reasons care is not withheld from the sick: if one seeks health, the unnecessary withholding of care is less reasonable than the unnecessary provision of it. It is because there are some who do benefit from care that care is given to all sick people.
In the same way there are those who will benefit from seeing the Tathagata, from hearing the Dharma instructed, from training, and other guidance. And there are those who will not - some people will develop sufficient understanding on their own, or fail to do so. But it is because there are those who do benefit from guidance that guidance is provided.