Productivity has nothing to do with looks, the ugliest people, works the hradest for they have no distraction from the world, don't believe me go look around you.
But, in natural genetic selection, two intelligent person, doesn't gurantee that they will produce, intelligent healthy offspring. One in the many, and if lucky the many can inherit the parent's genes. But in many cases, they will produce albinoes, down syndrome, autistic, intellectually or children with defects or deformity, in one or two of the offsprings they produce, and in some case; all the offsprings.
That means, a good fruit tree, not necessary produces good fruits all the time; nature is wise on this.