It cannot be required of every person to learn all of the Torah or even to understand all of what is learned.
All that can be required is that whatever one does learn should be correct Truth—not more or less or probable truth—but the kind of truth that will enable a person to be sure about which buttons he has to press and those that he has to avoid in an incompletely comprehended world.
It is not a matter of how much one knows but of how reliable and integral the knowledge is, no matter on what level.