According to evolutionary theory, from what I can see, a human being (or beings) who sees reality as it really is, for instance, a Buddha, is not any better adapted than a human being who has no interest in seeing reality as it is who, instead, is successful at the process of natural selection.
Our biological history says that we are shaped not to see true reality but, instead, to have perceptions that keep us alive by natural selection which we have to take seriously—at least that is the way the game is played which we seem to want to play.
Buddhism, on the other hand, says that we have the capacity to see and realize reality as it is and, to a lesser extent, also follow the not so prime directive of natural selection given that the animative principle of our body is true reality—not what is animated (i.e., the temporal body and the world it perceives through its sensory apparatus). This principle has to be directly intuited in and through itself because as far as our animated body is concerned this is its source just like electricity is the source of an electrical appliance’s operation.
In this regard we are fundamentally spiritual agents, but agents who are always unconsciously willing our self into an illusory body which, according to the Buddha, is empty in the sense of being for us only a relatively useful illusion, having no real inherent nature.
In spite of this assessment by the Buddha, rather than put more time into realizing reality as it is, we seem to insist on clinging to this corporeal construct and its world so that, as a consequence, we are always reborn many times into various kinds of illusory bodies according to our will and disposition. We are not open to any other view. Unfortunately, this is the life of an ‘ordinary person’ who only follows the way of the sensory mind. If we followed, instead, the Buddha's path we would save our self the trouble of being reborn.